By Frank Rich — New York Times.

FOR Barack Obama’s knee-jerk foes, of course it was his Katrina. But for the rest of us, there’s the nagging fear that the largest oil spill in our history could yet prove worse if it drags on much longer. It might not only wreck the ecology of a region but capsize the principal mission of the Obama presidency.

Before we look at why, it would be helpful to briefly revisit that increasingly airbrushed late summer of 2005. Whatever Obama’s failings, he is infinitely more competent at coping with catastrophe than his predecessor. President Bush’s top disaster managers — the Homeland Security secretary, Michael Chertoff, as well as the notorious “Brownie” — professed ignorance of New Orleans’s humanitarian crisis a full day after the nation had started watching it live in real time on television. When Bush finally appeared, he shunned the city entirely and instead made a jocular show of vowing to rebuild the coastal home of his party’s former Senate leader, Trent Lott. He never did take charge.

The Obama administration has been engaged with the oil spill from the start — however haltingly and inarticulately at times. It was way too trusting of BP but was never AWOL. For all the second-guessing, it’s still not clear what else the president might have done to make a definitive, as opposed to cosmetic, difference in plugging the hole: yell louder at BP, send in troops and tankers, or, as James Carville would have it, assume the role of Big Daddy? The spill is not a Tennessee Williams play, its setting notwithstanding, and it’s hard to see what more drama would add, particularly since No Drama Obama’s considerable talents do not include credible play-acting.

But life isn’t fair, and this president is in a far tougher spot in 2010 than his predecessor was in 2005.

When Katrina hit, Bush was in his second term and his bumbling was not a shock to a country that had witnessed two-plus years of his grievous mismanagement of the Iraq war. His laissez-faire response to the hurricane was also consistent with his political DNA as a small-government conservative in thrall to big business. His administration’s posture toward the gulf region had been telegraphed at its inception, when Dick Cheney convened oil and gas cronies, including Enron’s Ken Lay, to set environmental and energy policy. The Interior Department devolved into a cesspool of corruption, even by its historically low standards, turning the Bush-Cheney antigovernment animus into a self-fulfilling prophecy and bequeathing Obama a Minerals Management Service as broken as the Bush-Cheney FEMA exposed by Katrina.

Obama was elected as a progressive antidote to this discredited brand of governance. Of all the president’s stated goals, none may be more sweeping than his desire to prove that government is not always a hapless and intrusive bureaucratic assault on taxpayers’ patience and pocketbooks, but a potential force for good.

He returned to this theme with particular eloquence in his University of Michigan commencement speech 10 days after the Deepwater Horizon blowout. He reminded his audience that under both parties the federal government helped build public high schools, the transcontinental railroad and the interstate highway system, engineered the New Deal and Medicare — and imposed safety and environmental standards on the oil industry. Quoting Lincoln, Obama said that “the role of government is to do for the people what they cannot do better for themselves.”

We expect him to deliver on this core conviction. But the impact on “the people” of his signature governmental project so far, health care reform, remains provisional and abstract. Like it or not, a pipe gushing poison into an ocean is a visceral crisis demanding visible, immediate action.

Obama’s news conference on Thursday — explaining in detail the government’s response, its mistakes and its precise relationship to BP — was at least three weeks overdue. It was also his first full news conference in 10 months. Obama’s recurrent tardiness in defining exactly what he wants done on a given issue — a lapse also evident in the protracted rollout of the White House’s specific health care priorities — remains baffling, as does his recent avoidance of news conferences. Such diffidence does not convey a J.F.K.-redux in charge of a neo-New Frontier activist government.

Long before Obama took office, the public was plenty skeptical that government could do anything right. Eight years of epic Bush ineptitude and waste only added to Washington’s odor. Now Obama is stuck between a rock and a Tea Party. His credibility as a champion of reformed, competent government is held hostage by video from the gulf. And this in an election year when the very idea of a viable federal government is under angrier assault than at any time since the Gingrich revolution and militia mobilization of 1994-5 and arguably since the birth of the modern conservative movement in the 1960s.

This is why the more revealing strand of Rand Paul’s post-primary victory romp may have been his musings about BP, not civil rights law — although they are two sides of the same ideological coin. He called out Obama and his administration for sounding “really un-American” in their “criticism of business.” He asked that we stop the “blame game” over the disaster and instead just accept the fact that “accidents happen.” Much as Paul questioned the federal government’s role in ordering lunch counters to desegregate, so he belittled its intrusion into BP’s toxic private enterprise. But unlike the Civil Rights Act of 1964, the role of government in corporate regulation is a continuing battle, not settled law.

Hardly were those words out of Paul’s mouth than the G.O.P. gave him the hook. He dropped his scheduled appearance on last Sunday’s “Meet the Press.” Mitch McConnell, the Republican majority leader and Paul’s newly self-appointed minder, declared that his fellow Kentuckian had said “quite enough for the time being in terms of national press coverage.” Establishment conservatives have scrambled to portray Paul as either an innocent victim of a liberal media game of “gotcha” or an inexperienced citizen-politician who made the rookie mistake of conducting campaign interviews as if they were classroom seminars in Libertarian theory. We were told he really didn’t mean what he was saying, and that he certainly didn’t represent the G.O.P. or the Tea Party movement.

Whom are they kidding? Paul rightly described his victory as “a message from the Tea Party” that it was on the march “to take our government back.” And if he doesn’t represent the G.O.P., who does if not his most powerful supporters and ideological fellow travelers, Glenn Beck and Sarah Palin? Aside from saying no to Obama, the Republican Party has no ideas except Tea Party ideas, Rand Paul ideas. And as The Economist, hardly a liberal observer, put it, Paul’s views are those of “a genuine radical who believes in paring government down to the bone.”

The president of the American Enterprise Institute, the conservative think tank, codified the mission in apocalyptic terms last weekend. The new American “culture war,” Arthur C. Brooks wrote in The Washington Post, is not “over guns, gays or abortion” but pits “the principles of free enterprise” against the “European-style statism” he accuses Obama of fomenting. It’s a war that takes no prisoners: the A.E.I. purged the former Bush speechwriter David Frum after he broke with the strict party line.

The stakes are high. To win this culture war, the right must rewrite history — and not just that of the Bush response to Katrina. In his jeremiad, Brooks held only “government housing policy” responsible for the 2008 economic meltdown and gave a pass to what he regards as an already overregulated Wall Street. Palin has brazenly accused Obama of being in financial hock to Big Oil when it’s her own “drill, baby, drill” party that has collected three-quarters of Big Oil’s campaign cash for decades.

The Tea Party is meanwhile busy rewriting America’s early history under Beck’s tutelage by enforcing a vision of the Constitution tantamount to the Creationists’ view of Genesis. We must obey the words of the founding fathers literally — or what the Tea Partiers think those words to be. (Many Tea Partiers seem unaware that Medicare is a government entitlement postdating Tom Paine.) There can be no evolution or amendments. Any Obama initiatives are sacrilegious. All previous add-ons are un-American and must be pared away, from the Department of Education to the Americans with Disabilities Act. Michael Steele, the party chairman, attacked Elena Kagan for joining Thurgood Marshall in finding the original text of the Constitution “defective” because, among other defects, it countenanced slavery.

The only good news from the oil spill is that when catastrophe strikes, even some hard-line conservatives, like Gov. Bobby Jindal of Louisiana, start begging for the federal government to act, and act big. It’s the crunch moment for government to make its case — as Obama belatedly started to do on Thursday. But words are no match for results. As long as the stain washes up on shore, the hole in BP’s pipe will serve the right as a gaping hole in the president’s argument for expanded government supervision of, for starters, Big Oil and big banks. It’s not just the gulf that could suffer for decades to come.