Later in a restaurant before their plane to the convention takes off, John speaks to an intrigued, but guilty-looking Ann about all the thousands of people he has spoken to with common "platitudes" (such as love-thy-neighbor and turn-the-other-cheek). He describes the ways he has responsibly matured in his thinking and how he presently feels about "the people." He empathizes with the loneliness and spiritual hunger of the John Does:

What makes them come and listen and get up their John Doe clubs the way they do?....Maybe they're like me - just beginning to get an idea of what those things mean. I never thought much about people before. They were always just somebody to fill up the bleachers. The only time I worried about them was if they...when they didn't come in to see me pitch. You know, lately, I been watching 'em when I talk to 'em. I could see something in their faces. I could feel that they were hungry for something, you know what I mean? Maybe that's why they came. Maybe they're just lonely and wanted somebody to say hello to. I know how they feel. I've been lonely and hungry for something practically all my life.

In Norton's mansion, Ann profits from more gifts (presented as a "token of appreciation") from the political mastermind - a mink coat, a new contract, and a diamond bracelet. As Norton cleans his glasses, he ominously describes the launching of his Presidential candidacy within a new third party - to be announced by John Doe himself at the convention. The third party will be named the John Doe Party - bound for the White House with support from John Doe clubs - and "devoted entirely to the interests of all the John Does all over the country, which practically means 90 percent of the voters." Norton believes Doe will be the perfect front to use as his figurehead.

The scene of the convention's opening is accompanied with the singing of The Battle Hymn of the Republic. The infectious, selfless ideals of the campaign provide the bulwark for the proceedings, as a radio correspondent looks out of a sound-booth window high atop the floor to report: "An idea based on friendliness, on giving and not taking, on helping your neighbor and asking nothing in return."

John Willoughby brings flowers to Ann's mother, just missing Ann on her way to D. B. Norton's mansion. After declaring that Norton is "a nice man...he's done an awful lot for...", he fumbles for words to speak. He haltingly and shyly half-proposes to Ann via her mother, reproaching himself that the "real John Doe" would be more articulate and straight-forward:

John: Have you ever been married? Sure you have, gosh. That's pretty silly. Well, you must think I'm kinda batty...
Ann's mother: John, my husband said, 'I love you. Will you marry me?'
John: He did? (She nods) What happened?
Ann's mother: I married him.
John: Yeah, that's what I mean, see. It was as easy as all that, huh? Yeah, but look Mrs. Mitchell, you know, I love Ann and it's gonna be awfully hard for me to say it, 'cause, well, you know, she's so wonderful...and all the best I ever was was a bush-league pitcher. And, you know, I think she's in love with another man, the one she made up. You know, the real John Doe. That's pretty tough competition. I'll betcha he'd know how to say it alright. And me, I get up to it and around it and in back of it, but I never get right to it. You know what I mean? So the only chance that I've got is, well, if somebody could kinda give her a warning - sort of prepare her for the shock.
Ann's mother: You mean you'd like me to do it? Hmm?
John: Well, I was thinking that...Yeah, you know, sort of, break the ice?
Ann's mother: Of course I will, John.

Soon afterwards at Jim's Bar, Doe is tipped off to Norton's dictatorial, anti-democratic intentions by a drunk Connell. Admitting that he is a sentimental, patriotic "sucker" for The Star Spangled Banner and the country (he witnessed his father's sacrifice for his country during World War I): "A guy can say what he wants and do what he wants without having a bayonet shoved through his belly...And we don't want anybody coming around changin' it, do we?" The managing editor, who is "boiling" and "sizzling" mad, is reminded of the great giants of US history who fought to prevent the 'lighthouses' of freedom and democracy from becoming enshrouded in the fog of fascism - in a famous line:

I get mad for a lot of other guys besides myself. I get mad for a guy named Washington, and a guy named Jefferson and Lincoln. Lighthouses, John - lighthouses in a foggy world.

He informs John that Norton's "fifth column" is advancing and using John Doe in the march "to shove his way into the White House so he could put the screws on so he could turn out the lights in those lighthouses." He accuses Norton of being a "no-good dangerous skunk" and "unmentionable worm." Disbelieving, John denies the charges of power-mongering: "You must be wrong, Mr. Connell. He's been marvelous about the John Doe clubs." Connell knows that Norton already has the backing and the support of industrial and labor leaders that have arrived for the convention: "Wolves waiting to cut up the John Does." John can't conceive of Ann writing a convention speech for him that would nominate Norton for President on the John Doe ticket and establish a dictatorship. But Connell is very aware that Ann has received bonuses for supporting Norton: "Why, that dough-grabbin' dame would double-cross her own mother for a handful of Chinese yams!" John seizes his convention speech and rushes to Norton's residence to see for himself.

"John Doe" walks in on the gathering, a formal dinner party, and from the adjoining hallway overhears the scheming, political chicanery of Norton. The would-be power-grabber guarantees the John Doe vote for his candidacy to his influential guests: "We can count on anywhere between ten and twenty million John Doe votes...and nothing can stop us." He describes his fascist plans for the country:

These are daring times...We are coming to a new order of things. There's too much talk been going on in this country. Too many concessions have been made. What the American people need is an iron hand.

As he lifts his glass to toast a stunned Ann Mitchell, "the brilliant and beautiful lady who is responsible for all this," John comes into her view. He asks if she wrote the convention speech that he is to deliver, and she replies: "Yes, I did, John, but I had no idea what was going on." He remarks on her "swell bracelet" and then stalks around the table. He accuses the bigshots of cutting a "nice fat slice of the John Does," (thereby making himself "the prize stooge of the world"), and using the John Doe clubs "for (his) own rotten purpose." He also threatens to denounce and expose Norton at the convention:

And what's more, I'm going down to that convention and I'm gonna tell those people exactly what you and all your fine feathered friends here are trying to cook up for 'em - and I'm gonna say it in my own words this time.

With an angry glance at Ann, he rips up Norton's nominating speech. Norton counters by reminding Doe who the real fake is (with a Judas-like contract of "thirty pieces of silver"). He threatens to kill the John Doe movement if he must:

May I remind you that I picked you up out of the gutter and I can throw you right back there again?...Get off that righteous horse of yours and come to your senses. You're the fake! We believe in what we're doing. You're the one that was paid the thirty pieces of silver. Have you forgotten that? But I haven't. You're a fake, John Doe, and I can prove it. You're the big hero who's supposed to jump off tall buildings and things. Do you remember? What do you suppose your precious John Does will say when they find out that you never had any intention of doing it, that you were being paid to say so?

He threatens to use radio stations and the newspapers to "kill the John Doe movement deader than a doornail." Although disillusioned, Doe won't let their hypocrisy go unnoticed, or let the idealistic John Doe movement die. He fights for the one worthwhile "idea" that has been generated - the further existence of the clubs, and challenges them to squash the movement. He intends to tell the people the candid truth about Norton:

You mean to tell me you'd try to kill the John Doe movement if you can't use it to get what you want?...Well, that certainly is a new low. I guess I've seen everything now...You...think of deliberately killing an idea that's made millions of people a little bit happier. An idea that's brought thousands of 'em here from all over the country - by bus, and by freight and jalopies and on foot - so they could pass on to each other their own simple little experiences...Why, your type's as old as history - if you can't lay your dirty fingers on a decent idea and twist it and squeeze it and stuff it into your own pockets, you slap it down. Like dogs, if you can't eat something, you bury it! Why, this is the one worthwhile thing that's come along. People are finally finding out that the guy next door isn't a bad egg. That's simple, isn't it?...It may be the one thing capable of saving this cock-eyed world. Yet you sit back there on your fat hulks and tell me you'll kill it if you can't use it. Well, you go ahead and try. You couldn't do it in a million years with all your radio stations and all your power, because it's bigger than whether I'm a fake, it's bigger than your ambitions, and it's bigger than all the bracelets and fur coats in the world.

After having discovered Norton's real intentions, Ann sides with John, adding in a burst of cheering exhilaration: "You bet it is, John!" When John punches out Ted, Norton whistles to signal his para-military motorcycle corps (looking like Nazi stormtroopers) to pursue his antagonist. Ann rushes after John, apologizing and explaining: "I didn't know what they were going to do," but he ignores her pounding on his car's window.

In a dramatic brief scene at the convention, over 20,000 John Doe Club members have assembled for a rally on the Wrigley Field ball park field in Chicago during a steady drizzling rain, where they communally sing (Oh, Susanna!) and stand united together under black umbrellas. John makes his way into the stadium's proceedings [a familiar arena for baseball playing] and mounts the stage, just a few minutes before the arrival of Norton. He receives a tumultuous ovation-greeting, and then is drowned out by the singing of America's patriotic anthem (My Country 'Tis of Thee). He must wait patiently while a silent prayer is conducted for all that are absent - "the John Does all over the world".

Trucks screech to a halt outside the stadium during the prayer, bringing dozens of newsboys to distribute copies of Norton's newspaper (that have been printed in advance) at the rally. A supporters balloon is popped (exploded!) by one of the motorcycle troopers. The newspaper headlines soundly denounce Doe: "JOHN DOE A FAKE! MILLIONS VICTIMIZED!" Announcers in the soundbooth interpret the events below them. Doe is publicly humiliated as Norton outmaneuvers him and exposes the phoniness of the entire John Doe story. Norton's troopers surge onto the field as Doe struggles to speak to the incited individuals in the stadium. As Norton ascends onto the stage, Doe is pulled from the microphone and accused of being part of the "cheap racket...for the sole purpose of collecting dues from John Does all over the country" - the blame is placed on Connell and Ann. The sanctimonious Norton forces Doe to admit that he was paid for being an imposter, and that he didn't pen the suicide note. When left to defend himself and a lone voice from the audience urges: "Speak up, John, we believe you," Doe's loudspeaker wires are abruptly cut, leaving him helpless and unable to speak and counter the charges to the jeering throngs in the crowd. [The manipulations to encourage an audience for the radio speech to keep him alive are reversed here to create an ugly denunciatory scene.] The booing, scornful mob (laced with stooges) is quickly angered and embittered by the revelations - wet newspapers are hurled at him. Brutally rejected, he is struck square in the face with a tomato as he tells them: "Listen, John Does, you're the hope of the world." The Colonel saves John from further abuse by dragging him off the podium (and returning with him to their homeless abode under the bridge). Newspaper managing editor Connell cynically comments on the sudden crushing and "frameup" of the idealistic movement, brashly comparing Doe to Christ:

Well, boys, you can chalk up another one to the Pontius Pilates.

Ann cries in her mother' arms: "I should've been there. I could've helped him. He was so all alone." The aftermath of the defeat of the clubs is broadcast in news headlines: "JOHN DOE PROVEN FAKER! CLUBS DISBANDING." Posters and buttons for the movement flow down a sewage drain. A surrealistic montage of images assault John Doe's mind - accusations of "faker, racketeer, liar, cheat, imposter."

A broken, defeated and humiliated man, Doe decides that he will vindicate himself and fulfill the original threats of the letter by really writing a suicide letter and by really committing suicide and becoming a martyr for the movement. He believes he has nothing more to live for - Ann has deserted him and he has been misunderstood and 'crucified' by his own followers. On a cold, snowy Christmas Eve, he enters City Hall (unseen) ready to jump at midnight from a ledge on the huge building (a caroling group outside Norton's Christmas tree-decorated house sings Silent Night on the overlapping soundtrack). Major characters convene there on the tower's rooftop (up a flight of stairs from the 14th floor) to dissuade him from suicide - Norton with his political supporters, Ann for a last-minute appeal, the Colonel and Connell, and Bert Hansen and his wife.

When midnight strikes, John emerges (in a waist-down shot) from an inside office where he has written a suicide note. He posts it down a mail chute and walks onto the snowy roof - the quiet punctuated only by church bells ringing. He removes an envelope from his coat pocket: "To all John Does Everywhere" (a copy of the mailed letter) and smokes his last cigarette. (From the shadows, D. B. Norton and his followers watch expectantly.) As John Doe climbs onto the railing, Norton cautions him to reconsider the taking of his anonymous life:

I wouldn't do that if I were you, John. It'll do you no good. The Mayor has policemen downstairs with instructions to remove all marks of identification you may have on your person. You will be buried in potter's field and you will accomplish nothing.

They are told that their efforts to stifle his martyrdom are powerless: "I've already mailed a copy of this letter to Mr. Connell." John is pleased that they will be there to witness the rebirth of the John Doe movement.

Ann (feverish from a sick bed) screams at him to stop. She hysterically sobs and urgently begs him not to kill himself. In an emotional speech - one of the best in the film, she admits her love for him ("I love you, darling") and her awareness of the dangers that Norton represents. Ann admits, however, that Norton's presence there is evidence of the strength of the movement. She clings and clutches at him, almost threatening to jump with him if he does. She argues with Christian theology (Christmas chimes ring on the anniversary of Christ's birth) that "the first John Doe" has already died for the people - Doe is more valuable for the movement alive than dead. She implores him to live and fight to preserve "John Doe" ideals and their new birth:

John... John... Oh, John, don't do it! I love you. I love you, darling. Oh, please! Please don't give up. We'll start all over again. Just you and I. It isn't too late. The John Doe movement isn't dead yet. You see, John, it isn't dead or they [Norton's group] wouldn't be here. It's alive in them. They kept it alive by being afraid of it. That's why they came up here. Oh, darling! Sure, it should have been killed. It was dishonest. But we can start clean now. Just you and I. It'll grow John, and it'll grow big because it'll be honest this time. Oh, John, if it's worth dying for, it's worth living for. Oh please, John. Oh. Oh, please! Please, God help me! John, John, look at me. You wanna be honest, don't ya? Well, you don't have to die to keep the John Doe idea alive. Someone already died for that once. The first John Doe. And he's kept that idea alive for nearly 2,000 years. It was He who kept it alive in them. And He'll go on keeping it alive for ever and always - for every John Doe movement these men kill, a new one will be born. That's why those bells are ringing, John. They're calling to us, not to give up but to keep on fighting, to keep on pitching. Oh, don't you see darling? This is no time to give up. You and I, John, we...Oh, no, no, John. If you die, I want to die too. Oh, oh, I love you. Oh, John...

She faints and collapses in his arms. Mute, stunned, and helpless - and almost without a will of his own, Doe is finally encouraged to not give up by the "people" who step forward - the soda jerk Bert and his wife and other sympathizing friends. They confessionally plead with him to seek redemption by returning to the organized idealistic movement and reactivating the clubs:

Bert: Mr. Doe. You don't have to...we're with ya, Mr. Doe. We just lost our heads and acted like a mob.
Bert's wife: What Bert's trying to say is that we need you, Mr. Doe. There were a lot of us that didn't believe what that man [Norton] said. We were gonna start up our John Doe club again whether we saw you or not. Weren't we, Bert? And there were a lot of others that were gonna do the same thing. Well, Mr. Sourpuss even got a letter from his cousin in Toledo. (I got it right here, Mr. Doe)...Only, only it'd be a lot easier with you. Please, please, come with us, Mr. Doe....

As John Doe walks away from the ledge toward his supporters with Ann in his arms, after the John Doe club members have renewed their faith in him and he has decided to not commit suicide, Connell (with his fist) tells off the oppressive and evil Norton in the final line:

There you are, Norton! The people! Try and lick that!

The film ends to the finale (the last movement) of Beethoven's Ninth Symphony.

The other alternate endings:

• The film ends after the convention and Connell's epilogue quote: "Well, boys, you can chalk up another one to the Pontius Pilates"
  
• John leaps from the top of City Hall and is shown - after his death - cradled in the arms of the Colonel who bemoans: "You poor sucker, you poor sucker"
  
• After Ann pleads with him and faints (after her expression of love), John decides to abandon his suicidal plan and he carries her out to "start clean" or "start all over again"
  
• When Ann encourages him not to jump, John is transformed by the Christmas spirit. He offers his Christmas wishes to Norton, who surprisingly converts and orders Connell to print the real suicide letter (and the true story) in the newspaper. The Colonel concludes: "Well, looks like I gotta give the heelots one more chance"