With less than two months to go until Election Day, the battle for control of Congress is entering the final leg of a campaign season that is shaping up as one of the tensest and least predictable in years.
Just two years after the bitterly disputed 2000 presidential contest, and one year after the worst terrorist attack on American soil, the upcoming elections will offer an important window into the mood of the electorate at a unique time in the nation's history.
The summer's steady drip of bad economic news, a weakening in President Bush's approval ratings, and indications that growing numbers of Americans think the country is on the wrong track have all lately given Democrats a sense of momentum. But so far, this has yet to show up as a discernable edge in enough individual races to tilt the overall playing field, which remains tightly competitive.
Analysts say that while the focus on domestic issues such as the economy and healthcare may give Democrats an advantage, congressional Republicans may also have protected themselves with votes for bills on corporate accountability and prescription-drug benefits. And foreign affairs could steal back into the campaign at any time, which could give the GOP an edge.
What makes all this particularly nerve-wracking for both parties is the fact that Congress has not been this closely divided in seven decades: Democrats need a net gain of just six seats to win back the House, while Republicans are just one seat away from control of the Senate.
As a result, even the slightest shift in voter sentiment could have an enormous impact whether it's a souring mood causing some voters to turn on the president's party, or renewed patriotism, prompted by memories of the terrorist attacks, giving Mr. Bush and the GOP a boost.
"Any little thing [or] any unanticipated big thing could make all the difference here," says Norman Ornstein, a political analyst at the American Enterprise Institute in Washington. "So we're going to have a tension-filled fall."
This year's battle is also being waged within a relatively small number of races. Despite the fact that this is a redistricting year meaning congressional districts have all been redrawn to comply with new census data only 40 House seats out of 435 are likely to be competitive, according to the Cook Political Report, a Washington newsletter.
In 1992, the last redistricting year, more than 120 seats were up for grabs. The Senate is somewhat more competitive, with at least 15 close races out of 34 seats up this year.
Most open is the field for governorships, with 36 seats up this year. Republicans have been bracing for losses in the states, since the GOP is defending 23 seats, but some Democratic incumbents have lately become vulnerable as well because of growing state budget woes.
For much of the year, it seemed as though Sept. 11 and the war on terror might play a big role in the campaign. Although historically the party in the White House almost always loses seats in midterm elections, Bush's soaring popularity in the wake of the terrorist attacks seemed to be bolstering his party to an unusual extent.
In recent months, corporate scandals and a stock market decline have shifted the nation's focus back onto domestic issues, pushing Bush's ratings down and allowing Democrats to go on the offensive.
Still, although generic party matchups in polls currently show Democrats holding a slight lead, analysts say there's little indication that the public is blaming Republicans for the nation's economic woes.
"If Democrats score points, it will be on a kind of amorphous nervousness on the part of the voters," says Stuart Rothenberg, a Washington political analyst. "But the voters are not there yet. They haven't been upset long enough to look for a scapegoat."
Any noticeable improvement in the economy or stock market by November could make it harder for Democrats to gain traction on these issues.
And a number of other factors could potentially turn voters' attention back to foreign policy such as the escalation of debate over a war with Iraq, which will likely become a major focus as Congress returns this week.
"Iraq could become an issue," says James Zogby, president of the Arab-American Institute in Washington, who says he's already noticed the topic cropping up in certain congressional races. Because of the troop commitment involved, "if any foreign policy issue becomes a debating point this year, that's going to be it."
The most unpredictable factor, however, may be the looming anniversary of Sept. 11. Most analysts don't see the terrorist attacks becoming a campaign issue largely because there's no area of disagreement between the two parties. But the effect the anniversary has on the public's mood could influence the election, particularly if it engenders warmer feelings toward the president.
Tactically, it will also shorten the campaign season. Although Labor Day typically marks the point when voters begin paying attention to politics, next week's anniversary all but promises to wipe politics off the national stage, leaving campaigns in a strange kind of limbo for at least a week. This may make it harder for challengers to get their message across during what is usually the most critical phase of a campaign.
It may also force campaigns to maintain a more positive tone for several weeks.
"Between Labor Day and 9/12 or 9/13, it's probably dangerous for politicians to be too partisan or too negative," says Mr. Rothenberg. "So it shortens the campaign window."