You know the politics of energy are changing in the United States when the senior senator from the oil-soaked state of Louisiana publicly admits that the oil era is passing and "the transition to clean renewable energy [must] begin immediately." So said Democrat Mary Landrieu, responding to President Obama’s Oval Office speech of June 15. Landrieu’s words are remarkable, considering her long record of devotion to the oil industry. Like her state’s junior senator, Republican David Vitter, Landrieu seems never to have met an oil industry subsidy she didn’t like. In this, she remains far from alone. Recently she joined a majority of the Senate in extending $35 billion in subsidies to the industry, even as BP’s deep-sea well continued to gush tens of thousands of gallons of oil into the Gulf of Mexico.

And yet, as Landrieu’s rhetorical evolution shows, the old calculus on Capitol Hill may be shifting. Obama’s prospects for passing strong climate and energy legislation will only grow brighter if Republicans continue their self-sabotaging strategy of apologizing to BP, following Representative Joe Barton’s bumbling lead. But the White House must seize the opportunity this moment affords. The president did himself no favors with his vague, lackluster speech, though he did rebound nicely the next day, staring down BP big shots during a four-and-a-half-hour meeting in the White House to win $20 billion for a fund to compensate individuals and businesses damaged by the gulf disaster. The president also took a firm stand with his moratorium on deepwater drilling—earning not only the ire of Big Oil and its Congressional champions but a ruling from a federal judge in New Orleans to block the moratorium, now on appeal.

Will Obama continue this relatively tough line as he pushes for energy and climate legislation in Congress? He clearly understands the big-picture reasons the United States needs a green energy revolution. Politically, to rely on foreign oil leaves us hostage to events outside our borders, including the desire of some oil-rich states to smite the Great Satan by closing off supply. Geologically, experts say peak oil is either imminent or has already arrived. The easy-to-access petroleum on this planet has been exhausted, which is a big part of the reason BP was drilling so deep—nearly four miles beneath the earth’s surface. Economically, clean energy is a key to prosperity and competitiveness in the twenty-first century, as China and Germany clearly recognize.

But Obama has offered precious few specifics on how his administration plans to rise to this challenge, and the approaches on the table in Congress leave much to be desired.

Public anger at BP is real and unlikely to wane anytime soon. Popular support for clean renewable energy is broad and deep. It’s hard to imagine a better time for the president to stand up to the corporate chieftains whose greed and arrogance produced not only the BP blowout but the dysfunctional energy system plaguing this country. We have seen two different Obamas in recent days: the Obama of the Oval Office speech and the Obama of the showdown with the BP bosses. The latter Obama was a calm but fierce fighter, willing to stand up for ordinary citizens through words and actions that cannot be misunderstood. The future of America’s energy and climate policy—and perhaps of Obama’s presidency—will depend in no small measure on which Barack Obama we see more of in the weeks and months ahead.