John Kerry's stop-go campaign also means that the Democrats are unlikely to regain control of Congress, writes Conor O'Clery.
If America were a European-style parliamentary democracy, the Democrats would be sweeping towards victory in the US Congress, where the upper and lower houses are currently controlled by Republicans.
According to the latest poll, 46 per cent of voters plan to vote for the Democratic Congressional candidate, compared with 38 percent who say they will vote Republican. And Democrats are generally more favourable viewed than Republicans by a margin of 52 to 47 per cent, according to the poll conducted for the New York Times/CBS News this week.
But it's not quite as simple as that. With their presidential candidate failing to surge in the polls to provide the coat-tail effect and with a vast number of the seats virtually uncontested, the Democrats have only a slim chance of regaining the Senate, and almost none of taking the House.
In the Senate, Republicans hold 51 seats, the Democrats have 48, and there is one Independent who usually sides with the Democrats. A total of 34 Senate seats are being fought in this election for the six-year tenure a senator enjoys, but more than two-thirds of this number are expected to return the sitting members. Republican senators are retiring in Oklahoma and Colorado and a third incumbent is facing defeat in Alaska.
If Democrats take all three of these seats they could take control of the upper chamber. But Democrats still would have to retain five seats which are regarded as toss-ups, four of them in strong Bush country - South Dakota, North Carolina, South Carolina and Louisiana - and one in Florida.
None is in more danger than the seat of minority leader Tom Daschle of South Dakota. The Republicans have launched all out assault on Daschle's prairie fortress, hoping to topple the highest-ranking Democrat on Capitol Hill. In a breach of the Senate's old-style gentlemanly rules, Republican majority leader Bill Frist himself travelled to South Dakota to campaign for Daschle's opponent, John Thune, who is challenging Daschle as an "obstructionist".
Daschle has attempted to depict himself as sound on the national security question by running ads showing him getting a warm embrace from George Bush after the president's post-9/11 State of the Union speech. That was before Daschle became a critic of the war in Iraq. He has also been running ads trumpeting the federal 'pork' he has got from Washington for South Dakota.
His opponent, helped by well-funded conservative groups, has accused the Democrat of hiding a liberal agenda and of not supporting tax cuts. One of Thune's ads accuses the Senate majority leader of leading an assault on the president helped by such bogeymen for the Republican Party as Senator Edward Kennedy.
Much media attention is being paid to the Florida contest which pits Democrat Betty Castor, former president of the University of South Florida, against Republican Mel Martinez, a Cuban-American who was Bush's first secretary of Housing and Urban Development.
In North Carolina, former Clinton Chief-of-Staff Erskine Bowles is leading Republican Richard Burr. In Louisiana, Democrat Chris John is trailing Republican David Vitter. And in South Carolina, Republican Jim DeMint is slightly ahead of Democrat Inez Tenenbaum.
One Republican incumbent facing an uncertain future is Senator Lisa Murkowski of Alaska, a supporter of oil drilling in the Artic wild life refuge. She was appointed to the seat by her father Governor Frank Murkowski, which didn't go down well with voters. Ms Murkowski is in a dead-heat with Democratic challenger, former Governor Tony Knowles.
In Colorado, Democratic state Attorney General Ken Salazar has lost a comfortable lead to drop behind brewery magnate Pete Coors in a fight for the seat vacated by Republican Senator Ben Nighthorse Campbell. Last week, President Bush spent two days in Colorado campaigning for Coors.
In Oklahoma, Democratic Brad Carson is tied with Republican Dr Tom Coburn, whom he has branded an extreme conservative.
But the most high-profile Senate race and the one where the outcome is not in doubt, is that in Chicago where African American Barack Obama is certain to become the country's only black senator, and only the third since the civil-war.
He enjoys a lead of 45 per cent over his black Republican opponent, Alan Keyes, a 'blow-in' from Maryland and a talk show host who preaches a far right religious message. Keyes replaced the original Republican nominee, who dropped out amid a scandal over the publication of divorce papers which showed that he had enticed his wife to clubs where group sex was practised.
Obama stunned the Democratic convention in Boston with the soaring style and rhetoric of his keynote speech, giving rise to speculation that he could run for higher office in eight or ten years.
In the House, Democrats are down 11 seats and need a surge from Senator John Kerry nationwide to win back the assembly. Actually the Democrats need to win 12, following the last minute switch to the Republicans by one of their number, Rodney Alexander of Louisiana.
While all 435 seats in the US House of Representatives are up for grabs, and more Republicans than Democrats are retiring, only about 25 to 40 seats are really contested. About 200 Republican and 200 Democratic seats are considered secure.
California with 53 House seats has only one competitive race. Adding to the Democrats' struggle is the fact that six of the party's incumbents are put in danger by 'redistricting' in Texas and Democrats have already conceded one Texas seat by not putting up an opponent. The redrawing of the Texas map was the result of a forceful personal intervention in the Texas legislature by Tom DeLay, the Republican House majority leader in the US Congress, known as 'the Hammer' for his 'hit 'em on the head' approach to opponents.
The Texas `redistricting' has been described by the Cook report as a battering ram to increase the Republican majority in the House. Mr DeLay, whose control of the House is absolute, is in trouble however on Capitol Hill.
The ethics committee has twice censured DeLay's conduct in recent weeks. One report stated that DeLay appeared to link political donations to legislative action and improperly persuaded US aviation authorities to intervene in a Texas political dispute.
That was when he used the powers of the Homeland Security Department to establish the whereabouts of Democratic members of the Texas legislature who had secretly gone to Oklahoma in a futile effort to avoid compulsory attendance at a session called by the Republican majority to approve the 'redistricting'.
The Ethics Committee also found DeLay tried to persuade Congressman Nick Smith from Michigan to vote for a Medicare drug benefit in return for improper support for the Congressional bid of Smith's son.
The behaviour of DeLay and the uncompromising way the House is now run - Democrats complain that they cannot influence legislation and that they are frozen out of discussions - may explain why Congress members are falling in the public esteem.