Republican presidential nominee Mitt Romney points to President Barack Obama during the first presidential debate at the University of Denver, Wednesday, Oct. 3, 2012, in Denver. (AP Photo/Eric Gay)

It was not Romney versus Obama in the first presidential debate of 2012.

It was Romney versus Romney. And one of them prevailed.

A restrained Barack Obama, who went into the debate with a solid lead in the polls, and an even more solid lead in the battleground states, often seemed to be more of a spectator than a participant.

Obama’s reluctance handed Romney an opening that the Republican took.

Indeed, Romney took it to every side of every issue.

Mitt Romney was for government, but not for “trickle-down government.”

Mitt Romney was for cracking down on Wall Street, except when he was against the Dodd-Frank banking reforms.

Mitt Romney was for Romneycare, and against Obamacare.

Mitt Romney was for the 47 percent, and against them.

The liberal, moderate and conservative Republican who has been on all sides of all issues brought his commitment-free brand of politics to the national stage in the first of three presidential debates. Even by Romney standards, it was a dizzying performance.

Poor Jim Lehrer could not keep up. The moderator lost control of the debate at the start, when he let Romney demand more time to answer President Obama’s opening statement than Obama had used to deliver it, and he never got it back. “Excuse me, excuse me,” Lehrer said early on. Eventually, as Romney began dictated when and how Romney would answer questions, Lehrer simply said: “All right. All right.”

This is how it went:

ROMNEY: Jim, the president began this segment, so I think I get the last word.

LEHRER: Well, you’re going to get the first word in the next segment.

ROMNEY: All right. Well, but he gets the first word of that segment. I get the last word I hope. Let me just make this comment…

And so he did.

Debates have come apart at the seams before.

That’s usually when the candidate with greater experience and stature steers things back to the high ground.

But it did not happen Wednesday night.

A dialed-down, consistently cautious Obama watched Romney go through ideological changes faster than Madonna does costumes on a concert night. Yet, Obama rarely if ever called his challenger out—even when the Republican presidential nominee was prattling on about the head-spinning mash-up of FDR and Reagan: “trickle-down government.”

On a night when Obama could have closed the deal, 46 percent of uncommitted voters told NBC pollsters that Romney won the debate. CNN foiund a wider margin, with 67 percent pegging Romney as the winner.

What happened? Obama let Romney do what Romney needed to do: remake himself.

“Look,” Romney announced, “the reason I’m in this race is because there are people who are really hurting in this country.”

This was a constant theme for the son of privilege who made a quarter billion dollars practicing what his fellow Republicans decried as “vulture capitalism.”

Yet Obama did not mention “vulture capitalism.” Or Bain Capital. Or the 47 percent video.

That’s worth repeating: Barack Obama let Mitt Romney ruminate about how: “The people who are having the hard time right now are middle- income Americans. Under the president’s policies, middle-income Americans have been buried. They’re just being crushed. Middle- income Americans have seen their income come down by $4,300. This is a—this is a tax in and of itself. I’ll call it the economy tax. It’s been crushing.” And when Romney finished, Obama did not mention the 47 percent video.

And then Obama said: “You know, I suspect that, on Social Security, we’ve got a somewhat similar position.”

Mitt Romney did not correct him on that, and why would he?

The president could have played the Paul Ryan card.

Instead, he folded.

Obama was better when he challenged Romney’s bizarre claim that he wouldn’t take care of his wealthy friends by maintaining and extending tax breaks for the rich. The president’s best line of the night was: “Well, for eighteen months he’s been running on this tax plan. And now, five weeks before the election, he’s saying that his big, bold idea is, ‘Never mind.’ ”

Obama was strong, as well, when he countered Romney on the essential issue of Medicare reform.

After Romney emphasized that his reforms would not change things for current recipients of Medicare, Obama said:

[If] you’re 54 or 55, you might want to listen ’cause this — this will affect you.

The idea, which was originally presented by Congressman Ryan, your running mate, is that we would give a voucher to seniors and they could go out in the private marketplace and buy their own health insurance.

The problem is that because the voucher wouldn’t necessarily keep up with healthcare inflation, it was estimated that this would cost the average senior about $6,000 a year.

Now, in fairness, what Governor Romney has now said is he’ll maintain traditional Medicare alongside it. But there’s still a problem, because what happens is, those insurance companies are pretty clever at figuring out who are the younger and healthier seniors. They recruit them, leaving the older, sicker seniors in Medicare. And every healthcare economist that looks at it says, over time, what’ll happen is the traditional Medicare system will collapse.

That was solid, even muscular.

But then the president let the issue go.

Harry Truman would not have done that.

Harry Truman never debated Tom Dewey in 1948.

But as he battled Dewey is that remarkable race, the Democratic president never, ever let his Republican challenger define himself into the mainstream—as Romney worked so hard to do Wednesday night.

Truman ripped Dewey. And when he could not get a grip on Truman, he hung the record of an obstructionist Republican Congress around Dewey’s neck.

Truman was sometimes criticized for being too blunt, too aggressive, maybe even a bit undignified.

But Truman won, and he brought a Democratic Congress in with him.

Instead of standard “debate prep”—of the sort he got going into Wednesday night’s debate—Obama should before the next debate do a Truman course.

For more on the debate, read Richard Kim on Jim Lehrer’s bad night.