The birthers have come back to life.

Donald Trump has soared to the top of the Republican presidential polls, thanks in part to the whimsical candidate’s claim that he has hired investigators to hunt down President Obama’s birth certificate in Hawaii. He’s tied for first place with Mike Huckabee, who has said Obama grew up in Kenya. The fading Sarah Palin, swallowing her earlier disavowal of the birther libel, is now asking questions about where the president was born.

Let’s hope Trump’s gumshoes don’t succeed in locating the secret document, for if they do they will learn the horrible, gruesome truth: Obama was born a moderate. In fact — and I have this straight from the vital records people in Honolulu — he was the bastard child of an unholy union of pragmatism and centrism.

Of course, we don’t really need his birth certificate to know this. We need simply listen to his speech Wednesday afternoon, in which aides say he will endorse the contours of the Bowles-Simpson plan to tame the nation’s runaway debt. Though he occasionally struggled against his congenital reasonableness during his first two years in office, Obama blessing the debt commission’s bipartisan product of spending cuts and tax increases confirms him as a born moderate.

His embrace of the compromise debt proposal — and of the effort by the Gang of Six senators to put something like it into legislation — will be considered apostasy by true believers on both sides. But it dramatically increases the likelihood that Washington will solve its debt problem — and it strongly allies Obama with the independent voters who will determine the outcome of the 2012 presidential election.

For Obama’s would-be challengers, the president’s embrace of former Bill Clinton chief of staff Erskine Bowles and former Republican senator Alan Simpson of Wyoming could mean the loss of one of the last few issues on which they could best the incumbent. The economy has begun to improve, GOP views on foreign affairs have become scattered, and antipathy to health-care reform has been compromised by the fact that the most serious front-runner, Mitt Romney, championed legislation very similar to Obama’s.

The issue of the debt, and Obama’s refusal to propose a viable solution, had given Republicans a legitimate claim that the president was failing to lead. But House Budget Committee Chairman Paul Ryan took that advantage away from Republicans last week when he rolled out a plan that, in order to make room for tax cuts, proposed eye-popping cuts to Medicaid and a voucher-like program for Medicare.

It was, a senior White House official told me, “breathtaking.” Obama advisers, stung by criticism that the president punted on the debt, seized the second chance Ryan had given them to claim Obama’s birthright: the center.

Score another one for President Passive. Ryan vindicated Obama’s coy leadership, in which he waits for lawmakers on Capitol Hill to take the lead. “There’s no reward for showing up too early,” an Obama adviser said.

Ryan’s proposal has spooked all the Republican presidential aspirants, save former senator Rick Santorum (R-Fugheddaboudit). Ideologues who defend the Ryan plan, such as former George W. Bush adviser Peter Wehner, attempt to argue that those who oppose it oppose any entitlement reform.

But even mainstream conservatives such as Sen. Saxby Chambliss (R-Ga.), part of the Gang of Six, say the no-new-taxes Ryan plan is a nonstarter. “What he seeks to do is to, number one, balance the budget over about a 10-year period simply by reducing spending,” he said. “And you can’t do that. It’s not going to work.”

What Ryan has done, however, is boost prospects for the Bowles-Simpson plan as a reasonable alternative. “When folks look at the two plans side by side,” Bowles told me, “they see balance in ours.”

Obama’s embrace of Bowles-Simpson will open a new rift with his supporters on the left, including the Campaign for America’s Future, which has already begun an e-mail campaign, and the columnist Paul Krugman, who accuses Obama of defining “the center as being somewhere between the right and the far right.”

White House officials were not deterred by the critique. “We’re accustomed to it,” one said. “This is about economic realities, not politics.”

House Democrats will further strengthen Obama’s position by offering their own budget proposal, which relies more on tax increases. That leaves Obama alone in the political center — in a perfect place to triangulate. For a born moderate, there is no cozier place to call home.