DFL U.S. Senate candidate Al Franken has moved into his first solid lead over incumbent Republican Norm Coleman, according to a new Star Tribune Minnesota Poll.

The survey, conducted Tuesday through Thursday by Princeton Survey Research Associates International among 1,084 likely Minnesota voters, shows Franken leading Coleman 43 to 34 percent. Independence Party candidate Dean Barkley is supported by 18 percent of respondents.

Franken's lead is outside the poll's margin of sampling error, plus or minus 3.7 points.

For Coleman, there is little good news in the poll. The number of voters who view him unfavorably continues to grow, the number who see him favorably is falling, and his job-approval rating has slipped to 38 percent — his lowest ever in the Minnesota Poll.

Coleman led Franken by four points in last month's Minnesota Poll.

The new results stand in contrast to the findings of a SurveyUSA poll, commissioned by KSTP-TV and also conducted this week, that shows Coleman with a 10-point lead over Franken, 43 to 33 percent.

Citing that poll, the Coleman campaign called the Minnesota Poll and its methodology "flawed," campaign spokesman Luke Friedrich said.

"Minnesotans should take the Star Tribune poll for what it's worth," Friedrich said.

"This is an independent pollster who is respected across the country," Star Tribune editor Nancy Barnes said. "It's the same pollster who found the presidential race in Minnesota to be a dead heat last month. All polls have a margin of error, but on the whole we trust that these results have merit.''

The Minnesota Poll results suggest Franken may be riding the coattails of Democratic presidential candidate Barack Obama, who has widened a lead over Republican John McCain in polls across the country. But the advertising war in the race also appears to be a factor decidedly in Franken's favor.

Colleen Murray, a spokeswoman for the Franken campaign, called the poll "great news for people across Minnesota who are hungry for change in Washington." Franken's lead, she said, reflects the belief of Minnesotans that he will fight for the middle class in Washington and that Coleman hasn't.

Barkley's 18-percent showing represents a bump of five points from last month's poll and an attention-getting show of support for the third-party candidate who has spent far less time and money campaigning than the two leading contenders.

But in the three weeks since the last poll Barkley's name recognition hasn't budged. A third of likely voters in this week's poll still say they've never heard his name.

Chris Truscott, spokesman for the Barkley campaign, said they were excited by recent poll numbers.

"We're consistently moving in the right direction and that's a result of Minnesotans looking for something better," he said. "We just got our radio ads up, and we've got five debates coming. This campaign is just getting underway."

Ad wars doing damage

The new poll suggests that one reason for Franken's gain is voters' reaction to the abrasive advertising in the campaign.

The survey shows that 56 percent of poll respondents consider ads criticizing Franken to be "mostly unfair personal attacks." Only 42 percent said the same about ads criticizing Coleman.

Some of the ads by the Coleman campaign and national Republicans show Franken when he was an entertainer, cursing and ranting on political subjects. Others stress the tax and accounting mistakes of his private corporation when he was living in New York.

Said Franken supporter Lori Miller, a 46-year-old small-business owner from Staples: "I feel we need something new, and I feel like [Franken's] out for the middle class. I don't know if I really believe all the bad things they're saying about him."

The Rev. Philip Geoffrion, a pastor in Cokato, is a Republican who's tempted to vote for Barkley except for the fact that, as he said, "when he doesn't have a chance to win, I figure I'll waste my vote." For now, he's sticking with Coleman.

Barkley hurting Coleman

The poll shows that Barkley is drawing more votes from Coleman than Franken, although Franken would still be ahead of Coleman even if Barkley wasn't in the race.

More Barkley supporters, 49 percent, said they leaned toward Coleman than Franken, who drew support from 33 percent of them. In a head-to-head match without Barkley, Franken topped Coleman by 49 percent to 42 percent.

The poll detected a significant increase in Minnesotans who label themselves as Democrats. Forty-two percent of likely voters identified themselves as Democrats, compared with 27 percent who said they were independents, and 26 percent who said they were Republicans.

According to the poll, Coleman's support has slid among men and those in upper- and lower-income brackets. Last month, Coleman led Franken among men, 46 to 36 percent; in the recent poll Franken is ahead, 45 to 34 percent.

Coleman continues to get strong support from white evangelicals, but white Catholics are about evenly split between the two leading candidates. Both Coleman and Franken are struggling equally to keep their respective bases from drifting to the Barkley camp; each has the support of 78 percent of their party members, while 12 percent of Democrats and Republicans alike support Barkley.

And Barkley has cut into Coleman's former lead among independents, leaving them divided almost evenly among Coleman (34 percent), Barkley (33 percent) and Franken (29 percent).

David Roeser, 65, a retired General Mills mechanic who lives in Minneapolis, said he was for Barkley in part because of all "the crap" in the TV ads.

"This has really alienated me from both [Coleman and Franken]. I've read some of Franken's satire — I'm not a big fan of the stuff — and I've watched Coleman in Congress a bit," he said. "But these ads have turned me totally away. Barkley seems like more my kind of person."

Kevin Duchschere • 612-673-4455