WASHINGTON — Americans will know in a little more than a week who'll be the country's 44th president, but despite all the promises and the campaign bluster, they won't know until Jan. 20 and beyond how Barack Obama or John McCain would govern.
A landslide win for Obama, now suggested by the polls, could sweep more Democrats into Congress and give him a relatively free hand to change course at home and abroad on issues from taxes to Iraq.
A sinking economy, however, could force Obama to shift priorities, perhaps even delaying his promised tax increase on the wealthy or his expansion of health care to the uninsured. A resurgence of violence in Iraq could compel him to rethink his plan to withdraw U.S. troops.
On the other side of the crystal ball, a narrow win for McCain, the best possible outcome for him now suggested by polls, would set him up for a titanic fight with a Congress that seems sure to remain in Democratic hands.
McCain has a history of working with Democrats in Congress, but they'd be none too happy about watching the presidency slip from their grasp. It's all but impossible, for example, to see how McCain could get them to ratify his proposal to extend President Bush's tax cuts for the wealthy.
"He has very poor prospects," said George Edwards, a scholar of the presidency and a political scientist at Texas A&M University. "The Democrats would be extremely shocked and irritated if he won. His notions of tax cuts are likely to not go anywhere. His approach to health care probably would not be the one the Democrats would pick up on."
Ironically, though, McCain might be able to strike a bargain with congressional Democrats to extend the expiring tax cuts for those who make less than $200,000 a year, much as Obama wants to do.
A President McCain, like all presidents, would have more leeway on foreign policy than he would on domestic matters. Even there, however, he'd find Congress fighting him at every step and appropriations bill.
"After eight years of the Bush administration, there is an awful lot of animus on Capitol Hill toward the Republican agenda," said former Rep. Tim Penny of Minnesota, a Democrat who's turned independent and supports McCain. "It would be a tricky situation for McCain."
While either candidate could still win, polls this week pointed toward a big win for Obama, who now leads in every state that Democrat John Kerry carried four years ago and in many states that Bush won, including Colorado, Florida, Indiana, Iowa, Ohio and Virginia.
"If these numbers hold up, he could win the biggest Democratic landslide since Lyndon Johnson in 1964," said Peter Brown, the assistant director of the Polling Institute at Quinnipiac University.
Independent analysts such as Charles Cook of the Cook Political Report and Larry Sabato of the University of Virginia say the Democrats also could win a filibuster-proof 60 seats in the Senate and add as many as 30 seats to their majority in the House of Representatives.
What would that mean? If you like Obama, it means that you could be very happy. If you don't like him, you could be very scared.
"If he wins big, there will be some sense of a mandate. And if he's got a lot of Democrats in Congress, they would be inclined to go along with him," Edwards said.
Domestically, Obama's biggest push could be to overhaul the tax code, cutting taxes for individuals who make less than $200,000 a year and raising them on those who make more than $250,000.
Though the government's deficits are likely to soar thanks to the $700 billion upfront cost of the financial system bailout and probable recession-driven drops in tax revenues, Obama says the tax cuts are needed even more now as an economic stimulus.
Whether he can push through the tax increases on the wealthy, as many Democrats want to do, is another question, however.
When ABC's George Stephanopoulos pressed him on whether he'd push the tax increases if the economy were in recession early next year, Obama said, "No, no, no, no, no. . . . I think we've got to take a look and see where the economy is. . . . We're going to have to re-evaluate at the beginning of the year to see what kind of hole we're in."
Rep. Barney Frank, D-Mass., the chairman of the House Financial Services Committee, also said that concerns about the deficit should take a back seat to using government spending or tax cuts to stimulate the economy. Tax increases on the wealthy can come "later on," he said. "There are a lot of very rich people out there whom we can tax at a point down the road and recover some of this money."
Yet if Obama put off tapping that source of revenue, it would rob the government of the money he says he'd use to expand health care for the uninsured.
Obama's vow to pay for all his new programs could suffer another blow — or force another look at priorities — if he can't withdraw troops from Iraq and use that $10 billion a month elsewhere.
Across the changing chessboard, keeping one big promise could require breaking another.
In style as well, Obama could find himself at odds with congressional Democrats or his broader constituency for change.
That happened to Democrats Jimmy Carter and Bill Clinton, though both were more conservative than the congressional wing of their party, while Obama is at home with the liberal wing of the party that dominates on Capitol Hill.
"The challenge for Obama is how he can manage Congress," former representative Penny said. "Maybe he has that ability. But it's a big unknown. He's so new and has such a skinny legislative record."
One key test: If Obama could muster enough Democratic votes to pass legislation, would he still reach out for Republican votes, too?
"There's a lot of pent-up emotion and legislation waiting on Capitol Hill," Penny said. "If Obama allows the Democratic majorities on the Hill to set the agenda and call the shots, I think he could find himself disappointing a lot of voters who are looking to him to be a more conciliatory, bipartisan leader."
Neither party probably could get everything it wanted. Republicans likely could block Obama's plan of "refundable" tax credits to the working poor that would show up as checks; Democrats could block McCain's extension of tax reductions for the wealthy.
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