HELENA, Mont. — Republican Senate candidate Mike Taylor, trailing badly in the polls against incumbent Democratic Sen. Max Baucus, has decided to drop out of the race, The Associated Press learned Thursday.

The move was confirmed by two sources close to Taylor's campaign who spoke on condition of anonymity. Campaign spokesman Bowen Greenwood would not comment on Taylor's plans.

The move comes less than a week after Democrats began airing a TV ad accusing Taylor of a scam involving student loan money when he ran a beauty school in Colorado in the 1990s.

Polls have also shown Taylor trailing Baucus by 19 points.

It was not immediately clear whether the GOP would seek to have Taylor replaced on the ballot less than a month before Election Day. Democrats won a court battle in New Jersey to replace scandal-tainted Sen. Robert Torricelli on the ballot with former Sen. Frank Lautenberg.

Taylor's surprise decision all but assures Baucus re-election to a fifth term. The Libertarian and Green parties each have a candidate in the race, but they have done fund-raising or campaigning.

Jason Thielman, chief deputy secretary of state, said Republicans cannot replace Taylor on the ballot because the law does not allow such a move if a candidate withdraws within 85 days of the election.

However, write-in candidates can file up to 15 days before the Nov. 5 election, he said.

Baucus is seeking another term in a state with a decidedly Republican tilt and has won praise from President Bush for helping pass the administration's tax cut and for putting country ahead of politics.

Taylor, a state senator from tiny Proctor, has suggested Baucus is trying to convince Montanans he is a Republican. Analysts say Baucus' approach is simply smart politics.

The TV ad, unveiled last Friday by the Montana Democratic Party, is based on Education Department documents that concluded the beauty school provided loans to students enrolled in a program ineligible for financial assistance and failed to properly refund money when they left school.

The reports also said the Michael Taylor's Institute for Hair Design gave loans to students no longer attending classes or failing to meet academic standards, and failed to verify loan eligibility of some students.

The commercial, showing an old TV clip of a youthful Taylor demonstrating application of facial cream to a man, said Taylor profited from the mishandling of loan money, caused students to default on their loans and cheated taxpayers.

Taylor's campaign branded the ad libelous and slanderous, and pondered legal action. Janna Taylor, the candidate's wife, took responsibility Tuesday for clerical errors that she said led to the student loan problems.

"The paperwork errors were mostly mine, or else they were those of the company we hired to help with our paperwork," she said in a statement. "There is no way Mike lined his pockets with all the expenses associated with running that school."

The Baucus campaign insisted it had nothing to do with the ad.