Boston ? There are moments in Jon Stewart’s hilarious send-up of civic textbooks, “America (The Book),” when the truth pops up like a jack-in-the-box. Consider “The Daily Show” comic’s take on political campaigns:

“Although the skills needed to woo voters are at times diametrically opposed to those necessary to govern them, the expensive and arduous process exists for a reason: to ensure that those who wish to govern are, if not the most qualified our country has to offer, the ones who want it the most.”

This is more likely to elicit a groan than a laugh from witnesses to the political matchup of these “Skull vs. Bones” men. Neither is a slouch in the ambition category.

Yet those of us who watched all three debates saw more than ambition on display. When taken as a whole, these 90-minute appearances became a three-act play that put Bush at the center of an unexpected narrative.

It was the man we thought we knew who changed each time he went on stage as if he were still struggling to find the right way to play himself. It was the president, not his challenger, who seemed different in each debate.

Act One featured an edgy, scowling George W. astonished to find himself facing a tough critic after so many performances before adoring prescreened audiences. The TV cameras raised his lectern to the height of his opponent, but on the split-screen he shrank.

Act Two starred the incumbent on a tear, so belligerent and defensive that at times he seemed to be auditioning for the part of a disgruntled post office employee. “You can run, but you can’t hide,” may have worked for Joe Louis. In 2004, it’s a better phrase to direct at Osama bin Laden than John Forbes Kerry.

As for the final act? This Wednesday night debate looked less like “The O’Reilly Factor” and more like “Face the Nation” with a touch of “Oprah.”

Two men with matching ties and opposing views had memorized the prepared lines of their scriptwriters. “Being lectured by the president on fiscal responsibility is a little bit like Tony Soprano talking to me about law and order in this country,” said Kerry. “You know, there’s a mainstream in American politics and you sit right on the far left bank,” said Bush.

They offered different takes on health care, Social Security, gay marriage and even faith. For Bush, faith offers “calmness in the storms.” For Kerry, faith is less a comfort than a prod.

In Act Three there was yet another performance. This time, Bush entered stage right, straining for sunniness. He put on a (sometimes edgy) happy face.

I never expected that the president would provide what dramatists call the “through line” of this television drama. After all, George W. Bush has long been seen as simple and direct. What you see is what you get. He was cast in this campaign as the known quantity.

The man who shared the stage with him has been caricatured as a surfer in the wind. Kerry was cast as the unknown, the one to watch. Yet the senator appeared exactly the same in every debate: measured, cool, wordy, steady, unflappable. Like him or not, Kerry was himself. George? We hardly knew ye.

The polls tell you that Americans think the country is on the wrong track; the president’s job approval has slipped below the halfway mark. The Bush campaign decided that even those who think we’re on the wrong track will follow the old leader if they are unsure of the alternative. They chose to brand Kerry with a pair of flip-flops.

But over the course of these debates, we saw Bush as uncertain in his role as Kerry was steady. Is this what they call role reversal?

Toward the end, both men were asked what they have learned from the women in their lives. For Bush the lesson he was “To stand up straight and not scowl.” For Kerry, the lesson from his mother was “integrity, integrity, integrity.” One man remembered stage instructions; the other man remembered the call to character.

When the curtain came down, we went back to dueling ads and media sound bites. The images that we saw on television may not withstand the distortions. But for three nights, over three acts, we saw two candidates for the leading role of this country, side by side. On one side, Kerry. On the other side, the three characters named Bush.