Voters can be forgiven for assuming the courts may once again settle the presidential election.

New lawsuits over election rules pop up almost every day, along with reports of fraud or mischief. Thousands of lawyers are already at work for one side or the other, with more on call for Election Day.

About half of all adults surveyed in an Associated Press poll — 48 percent — said they think the election results will probably be challenged in court. The number is slightly higher among likely voters, with 54 percent saying a court fight is somewhat or very likely.

Six in 10 of those surveyed say it's likely there will be no clear winner in the presidential race by Nov. 3 — the day after the election, according to the poll conducted for the AP by Ipsos-Public Affairs.

A spokesman for Democratic challenger Sen. John Kerry (search) suggested that fear is misplaced.

"Our operating assumption is that there will be a clear winner," campaign aide Joe Lockhart said. "We expect this to be over on election night."

The six in 10 figure from the AP poll "is a reaction to coverage to some of the shenanigans that have been going on," Lockhart said.

Each side claims there are shenanigans on the other side.

Republicans, for example, point to obviously fake names added to voter rolls during massive registration drives this year, and note that election officials cannot locate many of the new registrants.

"Given all the fraud that we are seeing, there were certainly unlawful registrants and there may be attempts at unlawful voting," said Mark Wallace, deputy campaign manager for President Bush and a Bush legal strategist.

In battleground Ohio, the state Republican Party challenged the registrations of 35,000 voters last week, saying mail sent to the voters came back as undeliverable. Republicans say the unreturned mail could signal fraudulent registrations. Democrats say the GOP is targeting new voters registered by political groups supporting Kerry.

The GOP has withdrawn thousands of names, citing mistakes in its own computer system.

But lengthy hearings are still expected to take place in some counties, with voters whose listing is in doubt asked to prove they live at the listed address.

Republicans also plan to challenge the credentials of some individual Ohio voters at the polls, a tactic Democrats say could stray over the line to intimidation.

In Missouri, the Democratic-leaning group America Coming Together (search) distributed an estimated 100,000 fliers in black neighborhoods that implied, without specifics, that Republicans are out to suppress minority voting this year. The flier showed a black man being attacked with a fire hose.

Both sides have also filed lawsuits before the election, challenging voting rules or procedures in key states where Kerry and Bush are running roughly even. In Iowa, the state will hold a hearing Wednesday on a suit filed by five Republican voters seeking to tighten rules for counting provisional ballots.

Most of the approximately 40 lawsuits so far were filed by Democrats or outside groups with generally liberal politics.

Some of those pre-election lawsuits raise issues that could resurface once polls close.

For example, Democrats have tried, mostly without success, to loosen rules in some states for counting provisional ballots. The backup ballots will be used nationally for the first time this year, and in Ohio and a few other populous swing states they could determine the winner.

After the election, one side or the other may claim that provisional ballots were cast or counted incorrectly in one or more states. Disputes now over rules for showing identification at the polls or for affirming U.S. citizenship could also echo in new legal challenges after the election.

Other suits could allege problems with voter registrations severe enough to affect the outcome.

In the AP poll, about seven in 10 Democratic voters, 69 percent, say they think it's likely there won't be a clear winner on Election Day.

"I'm afraid it's going to be muddled," said Joanne Rettke, 75, of Bloomington, Ill.

"I don't feel good about it. I liked the good old days when we had a good, solid, clean election."

Almost six in 10 Republican voters, 56 percent, say they also worry about an unresolved election, according to the poll.

The AP-Ipsos poll of 1,000 adults, including 856 registered voters and 670 likely voters, was taken Oct. 22-24 and had a margin of sampling error of plus or minus 3 percentage points for the full sample, slightly larger for subgroups like registered voters.