How Obama and McCain Would Lead

They only look as if they inhabit our galaxy. In truth, the men who would be President have been running for months in a parallel universe, a place where a Chief Executive changes laws by waving a hand and reorders society at the stroke of a pen. "When I am President," the candidates declare — and off they go into dreamspeak, describing tax codes down to the last decimal point and sketching health-care reforms far beyond the power of any single person to enact. In their imaginary, reassuring cosmos, America is always a mere 10 years — and one new President — away from energy independence. And the ills of the federal budget can be cured simply by having an eagle-eyed leader go through it line by line. (See the next President's to-do list.)

Then one of them wins the election.

In an instant, the winner is sucked through a wormhole back into the real world. A world in which Congress, not the President, writes all the laws and gets the last word on the budget. Where consumers decide which cars to drive and how many lights to burn. And where the clash of powerful interest groups makes it easier to do nothing about big problems than to tackle them. Even the strongest, wiliest, most effective Presidents must change shape and shift direction to accommodate these and other forces. An ability to alter course without losing one's way is essential to presidential success. "I claim not to have controlled events," Abraham Lincoln wrote, "but confess plainly that events have controlled me." As the sailor President Franklin D. Roosevelt understood, only rarely does a fair wind blow squarely at the President's back. More typical is the gale blowing from dead ahead or the deceptively strong crosswind. Sometimes the best that one can do is inch forward at an angle while struggling to avoid running aground.

The next President, whether it's Barack Obama or John McCain, will take the helm amid a maelstrom. Testifying before Congress, former chairman of the Federal Reserve Alan Greenspan — not known for his colorful public statements — professed "shocked disbelief" at the "tsunami" that has plunged global finance into disarray. He predicted a deep recession that will cost jobs and devastate balance sheets across the economy — "much broader than anything I could have imagined." When the chief economic advisers to McCain and Obama met recently for a debate, they found little to agree on. But they shared the realization that the new President's options will be severely constrained by an economy in turmoil. Douglas Holtz-Eakin conceded that McCain's promise to balance the budget in four years is off the table. "The events of the past few months have completely thrown a wrench into that — there's no way round it," he said. Austan Goolsbee, who counsels Obama, spoke grimly of "the hole we've dug" as a nation.

It's impossible to say exactly how deep that hole will turn out to be — which makes it hard to say exactly how much of the next President's energy will have to go toward pulling us out of it. And the economy is far from the only unpredictable force the 44th President will contend with. Experts are forecasting a surge in the number of Democrats in Congress that would give Speaker of the House Nancy Pelosi and Senate majority leader Harry Reid the largest majorities either party has had since the early 1990s. This would obviously limit the options of a Republican President McCain. But Congress would be a complicating factor in the life of President Obama too. After all, the Constitution envisions a strong Congress, and that's just the way committee chairmen like it. After more than a dozen years of being stymied, first by Newt Gingrich and then by George W. Bush, congressional Democrats are bursting with pent-up ambitions and long-deferred dreams. Some are epic undertakings that would affect every American for decades — like the proposal to impose a cap on carbon dioxide emissions and put a price on permits to burn fossil fuels. Or the goal of completely reorganizing the way the U.S. manages health care. Other, smaller projects involve large amounts of controversy — like a bill that would allow federal funds to pay for abortions. And expansion of embryonic-stem-cell research. And a "path to citizenship" for millions of immigrants who are living illegally in the U.S.

See pictures of Obama's campaign behind the scenes.

See pictures of McCain's final push.