Gov. Mark Dayton heads into re-election with the highest job approval rating of his term, according to a new Star Tribune Minnesota Poll.

The poll found that 58 percent of Minnesotans think Dayton is doing a good job as governor, with 29 percent saying they disapprove. Those numbers come after the governor orchestrated an income tax increase on the wealthy and after the troubled rollout of the state's health care exchange that opponents hoped would diminish his popularity.

"Given that it's been a challenging couple of months with MNsure and the light-rail line and the like, I think it shows people are looking at the big picture of how the state is doing overall," Dayton said. "I'm certainly gratified by these numbers, but there's a lot more work ahead. I think Minnesota has made excellent progress in jobs and education but we have a lot more to do in those and other areas as well."

Dayton is preparing for a legislative session later this month and a re-election campaign where Republican rivals will try to put a dent in those ratings.

The task may be formidable. More than half of independents give Dayton high marks, along with a fourth of Republicans and 64 percent of those with no political affiliation. Nearly 90 percent of Democrats say that, more than three years since he took office, they like the job Dayton is doing.

His job rating has also proved durable. Dayton is up 1 percentage point from June, when he was at 57 percent and his disapproval stood at a slightly higher 31 percent. He has fallen below 50 percent only once during his term, last February, but rebounded over the summer.

"I'm surprised. I think he's doing quite well," said Joan Sims, an 84-year-old from Prior Lake. Sims said she didn't have very high expectations for Dayton, who, she recalled, gave himself a failing grade when he served as a U.S. senator.

"I like the fact that he sticks to his guns," she said.

The poll surveyed 800 Minnesota adults between Feb. 10 and 12 and has a margin of sampling error of plus or minus 3.5 percentage points. Three-fourths were reached through a land line, one-fourth by cellphone. It included 39 percent Democrats, 30 percent Republicans and 26 percent of Minnesotans who said they were independent or identify with a third party. Those numbers track with recent Minnesota voting trends.

Dayton has moved up in Minnesotans' estimation since he won the governorship with just 42 percent of the vote and after a monthlong recount. However, solid approval ratings are no guarantee of easy election. Republican Gov. Tim Pawlenty scored a 58 percent approval rating in July 2006, but barely survived a three-way election that November, with a victory margin of 1 percent over his Democratic opponent.

Republican Ben Golnik, president of the Minnesota Jobs ­Coalition, said Republicans will have many issues with which to hit Dayton in coming months. The full brunt of the health exchange rollout, the potential for rising property taxes and the effect of broader tax increases all will hurt the DFL governor in November, he said.

"The national mood will continue to benefit Republicans," Golnik said.

'A good place to start'

Dayton, too, anticipates that his ratings will go down, once the campaign against him starts in earnest.

He said his 29 percent statewide disapproval rating "won't last long once the independent expenditures start savaging me. But it's a good place to start."

So far, Dayton appears to have escaped being linked to President Obama in a way that damages his political credibility. Minnesotans have soured on the Democratic president, but still approve of their Democratic governor. The president's job approval rating slipped below 50 percent in the Minnesota Poll for the first time since he took office.

Asked whether they had a favorable, unfavorable or neutral opinion of Dayton — a slightly different gauge of popularity than job approval — 36 percent of Minnesota adults said they thought favorably of Dayton. An equal percentage said they were neutral about him. Only 24 percent said they had unfavorable opinions of him, giving him the lowest "unfavorable" opinion percentage of any political figure the Minnesota Poll surveyed.

In the poll, Dayton received far higher marks than Obama, who won Minnesota by 8 percentage points just 15 months ago. According to the poll, fully half of Minnesotans disapprove of the job Obama is doing and only 43 percent give him high marks.

Those bad grades for Obama stretch across most demographic groups the Star Tribune surveyed. In contrast, almost all groups gave Dayton approving job marks.

For Dayton, the exceptions were among Republicans, men, and outstate Minnesotans.

Richard Lacher of Dora Lake is among those who think Dayton is doing a "terrible" job.

"He's doing about as well as he did as senator and he gave himself an F grade," he said. Lacher, 72, said he likes to think of himself as in the middle politically, but finds himself leaning more conservative all the time.

Lacher said he doesn't like that Dayton raised taxes. He said the governor will likely oppose the PolyMet mining project planned for northern Minnesota, although the governor has been publicly neutral on it. And he is frustrated with MNsure, the Minnesota health exchange ushered in by the federal health care overhaul.

"MNsure — $160 million for a website? Excuse me," he said. "We had a perfectly good health care system going into it."

But Dayton has a fan in Roger Golby, 64.

"I think he is doing a fine job," said Golby, a DFL Senate district chair from Annandale in Wright County. He said he likes the fact that under Dayton, all-day kindergarten is now free, and that his wife has been able to find affordable health insurance through MNsure. He particularly appreciates that ­Dayton has reached out to places outside the Twin Cities.

"Some of the former governors, you know who were they were but you'd never see them," Golby said.

Rachel E. Stassen-Berger Twitter: @RachelSB