WASHINGTON -- Montana Sen. Max Baucus is stumping for fellow Democrat Jon Tester in a new television ad, saying he disagrees with Republican Sen. Conrad Burns on ''a lot of things.''

''You might have heard those ads from Conrad Burns using my name,'' Baucus says in the spot, which was to begin airing Tuesday. ''Well, let me be clear -- I support Jon Tester.''

Burns, a three-term Republican incumbent, is in the re-election race of his career against Tester, whose campaign paid for the ad. Polls over the last few months have showed the two even or Tester slightly ahead.

Recent Burns radio ads have used Baucus's name, referring to money both senators have secured for the state. None of the ads say Baucus is endorsing Burns.

''Max Baucus and Conrad Burns have been good neighbors,'' said one radio ad that aired in Butte. ''Senators Baucus and Burns secured funding through experience and seniority.''

The Burns campaign has also sent out direct mail detailing issue areas where Baucus and Burns agree. The pieces compare Tester's issue positions to Burns and Baucus, saying Tester is more liberal than both senators.

''I don't like it,'' Baucus said last week in an interview with The Associated Press. ''I take my reputation very seriously and I don't want to mislead Montana voters. And that's what he's doing.''

Baucus came under similar fire from Republicans when he last ran for re-election in 2002. His opponent that year, Republican Mike Taylor, criticized the Democrat for ''trying to convince people he's Republican'' when Baucus evoked then-popular President Bush in campaign ads.

Erik Iverson, Burns' senior campaign adviser, said the Burns ads ''in no way, shape or form suggest Max Baucus has endorsed Conrad Burns.''

''Conrad Burns doesn't want Max's endorsement nor has he ever sought Max Baucus's endorsement,'' Iverson said. ''This to me is a bit of feigned indignation.''

Tester spokesman Matt McKenna would not disclose how much the campaign spent on the ad, but said it is running statewide and ''you would have to be under a large rock in a deep hole not to see this ad over the next week.''

Baucus has recorded similar radio ads for the Tester campaign.

On the Net: www.testerforsenate.com/media/clarity.wmv