President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE and many Republicans have repeatedly targeted special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's investigation as politically motivated and full of bias, but those criticisms do not appear to have shifted the public opinion against the special prosecutor.

In a new Hill.TV/American Barometer poll released Friday, 58 percent of registered voters said they believe that Mueller's inquiry into Russian interference in the 2016 presidential election is unbiased, while 42 percent characterized the probe as biased.

As might be expected, the results were split largely along party lines.

Of respondents that identified as Republicans, 77 percent said they think the Mueller probe is biased and designed to hurt the president while only 23 percent saw the investigation as fair.

Democrats were even more lopsided in their support for the special counsel.

Eighty-seven percent of those surveyed who identified as Democrats called Mueller fair with just 13 percent describing him as being biased.

Independents continue to view Mueller positively with 60 percent saying he is unbiased and 40 percent saying the opposite.

"What we're seeing is that the American public really wants a full investigation," Mallory Newall, research director at Ipsos Public Affairs said Friday on "What America's Thinking."

The latest American Barometer findings are comparable to a June poll conducted by Morning Consult which found that 40 percent of respondents believed that Mueller's investigation was biased.

"The polls are remarkably consistent on Mueller and the job that he's doing on the Russia investigation," Karlyn Bowman, a senior fellow at the American Enterprise Institute told "What America's Thinking" host Joe Concha. However, it is possible that public confidence in him may wane over time, she added.

"What I think we're beginning to see just little hints of is fatigue with the investigation and we'll be watching that going forward, but at this point, he has strong support for continuing the investigation and he seems to rise above politics in Washington right now."

Mueller's current public standing is a contrast to what Americans once thought of Kenneth Starr, the former independent counsel who investigated then-President Clinton in the 1990s.

In polling conducted by Gallup, a majority of respondents never said they viewed Starr favorably. His negative ratings skyrocketed and remained high throughout the duration of his tenure.

Mueller, a former FBI director, has shown little interest in his public image since he was appointed to explore Russian involvement in the 2016 campaign and any Americans' cooperation with the influence operation, making no public statements and ensuring that his team refrains from leaking confidential information to the news media.

The investigation has thus far yielded eight guilty pleas and dozens of indictments, most of them for Russians accused of hacking or making fraudulent statements. Trump supporters have argued that Mueller's targets who were affiliated with the president were not charged for their actions to help his former campaign.

Last week, Trump's former personal attorney, Michael Cohen Michael Dean CohenJudge orders Eric Trump to comply with New York AG's subpoena before Election Day A huge deal for campaign disclosure: Trump's tax records for Biden's medical records Our Constitution is under attack by Attorney General William Barr MORE, was sentenced to three years in prison for illegal payments to two women who claimed to have had sexual encounters with the president before his political career began. Cohen has said that Trump directed him to make the payments. After initially and falsely claiming to have no knowledge of the transactions, Trump has said he did not instruct Cohen to break the law.

The American Barometer poll was conducted Dec. 15-16 among 1,000 registered voters by HarrisX for Hill.TV. It has a sampling margin of error of plus or minus 3.1 percentage points.

— Matthew Sheffield