Now, more than in 2000, one-party rule is the name of the game. For the first time since the 1920s, the Republican Party has won control of the White House, the Senate, and the House of Representatives in consecutive elections.
And even though the margin of victory for each remains narrow, it grew in all three, signaling profound implications for governance in America over the next four years. Even when George W. Bush won the presidency in 2000 without winning the popular vote, he plowed ahead with a bold agenda. Expect nothing different in a second term, analysts say.
"Just think of last time," says George Edwards III, a presidential scholar at Texas A & M. "He didn't hesitate, he didn't try to govern from the center, and won't do it this time."
Bush-watchers expect a period of conciliatory talk, in which the president speaks of the need to heal the nation's deep partisan divide and come together for the national good at a time of war abroad and threat to security at home. But the center in American politics is an ever-lonelier place; witness the defeat or retirement of many of the remaining conservative Democrats in the House and Senate. If Bush has learned anything from the last four years, it is that he can play hardball and win. The defeat of the Democrats' Senate leader, Tom Daschle of South Dakota, is the icing on Tuesday's GOP sweep - and exacerbates the Democratic Party's disarray.
Historically, second presidential terms are usually not as successful as first terms, when it comes to passing major new programs. Second terms are usually about completing unfinished business - and in Bush's case, the plate is full. The Iraq war remains front and center. As Bush enters his second term in January, Iraq will be holding elections, a crucial test of that nation's ability to transform itself into a functioning, self-governing nation.
On the domestic agenda, expect "tax cuts as far as the eye can see," says Marshall Wittmann, a former Republican activist and now a senior fellow at the centrist Democratic Leadership Council. "The only constraint that Bush has at this moment is the deficit, but that doesn't seem to have stopped him in the past."
More specifically, Bush could move to make permanent the elimination of the estate tax and institute broader tax reform, making the rate system "flatter." Other legislation that was bottled up in the first term, such as the energy and highway bills, will likely move. One big unfinished agenda item from Bush's first term is reform of Social Security, specifically the establishment of private accounts. Bush and the Republicans can also be expected to defund discretionary programs, limiting the Democrats' ability to provide money for new social programs.
But even as Democrats are licking their wounds from an Election Day with few bright moments, they can take some solace in looking ahead to a second Bush term in which the buck firmly stops at the GOP's front door. The Republicans will now be even more firmly in charge than they were during the last four years (which included a period of Democratic control in the Senate); Bush's high-wire act in Iraq contains a big risk of public disillusionment.
"Republicans have no more alibis, no excuses," says Mr. Wittmann. "The one thing we do know is there's a tendency for a party with this much power to overreach."
Whit Ayres, a Republican pollster, sees the bigger majorities in the House and Senate as easing his party's ability to govern - and a signal to Democrats that it's better to go along than to fight. Bush's majority of the popular vote - making him the first presidential candidate to achieve that feat since his father, in 1988 - represents an endorsement of his agenda by the people, he says.
"The Senate now looks like it will be somewhat governable, as governable as it ever gets," says Mr. Ayres. "The clear message [of Tuesday] is that blind obstructionism did not work. It cost the Democrats seats. So I hope the Democratic minority will see that reasonable cooperation is a better bet for their electoral future."
Some analysts say Bush would be smart not to "go for broke" with a conservative ideological agenda in the new Senate, instead opting for a moderately conservative agenda that antagonizes the Democrats a bit less. If, as appears likely, there is one or more vacancy in the Supreme Court in the next four years, Bush still will need to make compromises to get his nominee confirmed by the Senate. The larger Republican majority will still not be close to the 60 seats needed to end a filibuster; Bush will need cooperation from some Democrats.
"He didn't propose what I consider to be a bold agenda in the campaign, [which was] pretty well established already," says Stephen Wayne of Georgetown University. "The issue is not will he be bolder, but will he be more willing to compromise to achieve half a loaf rather than the whole loaf, and put this down as a credit ... in the legacy column?"
On Iraq, one of the first orders of business in the new Congress will be to pass a supplemental appropriation to fund operations there. Ironically, while Iraq was a big campaign issue, foreign policy analysts see the outcome of the US election as mattering little to the next president's options there.
"My great fear was that Kerry would get elected, this thing would spin out of control, and the Republicans would blame the Democrats and say, 'We were on our way to winning and the Democrats blew it,' " says John Mearsheimer of the University of Chicago. "That's the argument they would have made and hung this albatross around the neck of the Democratic Party for the next 30 years."
One policy area in which the Republican Party may not have to pay the cost is Social Security. The transition to private or partially privatized accounts, if such a plan goes through, will be extremely expensive. But, says Professor Edwards, "it doesn't mean a disaster for Republicans, because the crunch will not have hit in four years."
• Faye Bowers contributed to this report.