A majority of likely voters believe that special counsel Robert Mueller’s investigation into Donald Trump’s possible collusion with Russia is fair, while almost a third called it biased in a new Star Tribune/MPR News Minnesota Poll.

The results mirror voters’ overall feelings about the president, most of whose time in office has been shadowed by the Russia probe. Just over half have unfavorable opinions of Trump, while a third view him favorably.

Minnesotans’ take on the fairness of the investigation hasn’t budged since a Minnesota Poll in January, when the split was about the same. Mueller was named to oversee the investigation in May 2017.

Attitudes about Mueller’s inquiry are deeply partisan.

Eighty-eight percent of those polled who backed Democrat Hillary Clinton in the 2016 presidential election described it as fair, while seven in 10 Trump voters disagreed. The gap between respondents who identified themselves as Democrats or Republicans was nearly identical.

The telephone poll of 800 likely voters was conducted from Sept. 10 to 12 and had a margin of sampling error of plus or minus 3.5 percentage points.

Doug Anderson, 80, a retiree in Austin who was polled, is a Trump supporter who thinks it’s past time for the investigation to end. He has no confidence in Mueller.

“He worked for [former President Barack] Obama, and I don’t trust Obama,” Anderson said.

The special counsel served as FBI director under Obama and former Republican President George W. Bush.

Anderson believes Trump’s assertion that it was Democrats who colluded with Russia before the 2016 election. Their motive, he said: “They’re just trying to get something on President Trump.”

Carol Ford doesn’t buy it. The 58-year-old secretary and organic farmer from Milan said Mueller has “a proven track record of leading this kind of impartial investigation.”

“Anyone who wants to whine about this being unfair,” she said, might be worried “that the truth he brings out won’t be something they like.”

Ford said the drama that began before the election and has surrounded the investigation has been unsettling. “I feel like our democracy is in jeopardy, and that’s a sobering thought,” she said. “It’s hard to know how all these cards are going to fall.”

Four former Trump campaign associates — Michael Flynn, Paul Manafort, Richard Gates and George Papadopoulos — pleaded guilty in Mueller’s investigation. Thirteen Russians, 12 Russian intelligence officers and three Russian companies were charged.

Trump has repeatedly called the inquiry a “rigged witch hunt.” After Manafort entered a plea deal on some charges last Friday, Trump took to Twitter to call the special counsel “highly conflicted.”

The poll found Hennepin and Ramsey County residents were most inclined to conclude that Mueller’s inquiry is fair.

The highest percentage of respondents who called the probe biased — 39 percent — live in northern Minnesota. But more in that region also concluded that it is fair.

Age was a significant factor in people’s views. The highest level of support for the inquiry came from younger voters. Among those who are 18 to 34, two-thirds sided with Mueller.

In every age group, however, those who called his work fair outnumbered those who did not agree.

A CNN Poll conducted Sept. 6-9 found that 36 percent of Americans had a favorable opinion of Mueller, up from 32 percent in June.

Half of those polled for CNN said they approve of the way Mueller is handling the investigation. That was the highest approval level in the eight CNN polls taken since December 2017.