A majority of polled voters say special counsel Robert Mueller has a conflict of interest because of his past ties to former FBI Director James Comey, according to the latest Harvard CAPS-Harris survey.

When asked if Mueller has a conflict of interest "as the former head of the FBI and a friend of James Comey," 54 percent responded that the "relationship" between the two amounts to a conflict of interest, including 70 percent of Republicans, 53 percent of independents and 40 percent of Democrats.

Comey succeeded Mueller as FBI director and the two have been described as "brothers in arms" for their working relationship, which dates back to the early 2000s, although the extent of their personal relationship is unclear.

Comey and Mueller were among the senior law enforcement officials who threatened to resign over a Bush-era domestic surveillance program, an episode that culminated with Comey rushing to the hospital bed of then-Attorney General John Ashcroft to beat White House officials who were on their way there.

"The special counsel has serious perception issues as a clear majority now see him as having a conflict of interest," said Mark Penn, co-director of the Harvard CAPS-Harris survey.

While Mueller is not universally known outside of Washington, he still has a positive favorability rating, with 34 percent viewing him favorably against 31 percent unfavorable, according to the poll.

A Washington Post-ABC poll in early November found that 58 percent approve of Mueller's investigation. That poll showed a significant different among parties, with 78 percent of Democrats approving of the probe, but 56 percent of independents and 38 percent of Republicans disapproving.

In the Harvard CAPS-Harris survey, a plurality of voters, 36 percent, said Trump and his allies are getting harsher treatment from the special counsel than Clinton and her aides received during the FBI investigation into her handling of classified material. Twenty-five percent said both parties are getting the same treatment, 24 percent are unsure and 15 percent said the president is getting more lenient treatment.

Comey cleared Clinton of wrongdoing and one of her top aides, Cheryl Mills, received an immunity deal during the investigation. Mueller's probe so far has resulted in guilty pleas from former national security adviser Michael Flynn, as well as former campaign adviser, George Papadopoulos, both of whom are cooperating with the special counsel. Former campaign chairman Paul Manafort and one of his top aides, Richard Gates, face a litany of serious charges pertaining to alleged financial crimes.

While most of the focus of the special counsel investigation has been on Trump officials, Mueller's team has reportedly interviewed British spy Christopher Steele, who compiled an anti-Trump opposition research memo based on interviews with Russian officials that was paid for in part by Clinton and the Democrats.

Republicans have been demanding answers about whether the FBI and Department of Justice (DOJ) used that dossier as part of its investigation into the Trump campaign or to obtain a Foreign Intelligence Surveillance Act court warrant to spy on the new administration during the transition.

Voters are uncertain about whether the investigations into Trump World were spurred by the dossier. Thirty-seven percent said the investigation was started based on other information, 37 percent aren't sure and 25 percent said the dossier provoked the investigation.

But when asked if "the part of the Justice Department responsible for the Hillary Clinton email investigations, and that is supervising the Mueller investigation, is resisting providing Congressional investigators with information on payments for the Fusion GPS dossier, unmasking of officials and other issues," 63 percent said they believe the DOJ is refusing to provide Congress with the information it has requested.

Still, 76 percent of voters say the special counsel was right to prosecute Flynn and 59 percent say he deserves jail time.

Flynn has pleaded guilty to lying to the FBI about his contacts with Russians and is a cooperating witness in the special counsel's investigation.

Three-quarters of voters say they believe Mueller is building an obstruction of justice case against Trump for reportedly asking Comey to go easy Flynn.

But 60 percent of voters say that "a comment to the FBI director that he should consider letting Flynn off the hook" is not enough to constitute obstruction of justice.

"To impeach the president, the public says [Mueller] needs to find concrete actions that [Trump] obstructed justice beyond his one-on-one conversations with Comey, who is at best a controversial figure," said Penn.

Democrats have argued that Trump fired Comey in an effort to end the investigation and that his dismissal is tantamount to obstruction of justice.

Seventy-six percent say they believe Mueller is still trying to prove that Trump campaign officials colluded with the Russians, but only 35 percent believe he's found evidence of this. Thirty-eight percent say they don't believe Mueller has found evidence of collusion and 27 said they don't know.

The Harvard CAPS-Harris online survey of 1,995 registered voters was conducted between Dec. 8-11. The partisan breakdown is 36 percent Democrat, 32 percent Republican, 29 percent independent and 4 percent other.

The Harvard CAPS-Harris Poll survey is a collaboration of the Center for American Political Studies at Harvard University and The Harris Poll. The Hill will be working with Harvard CAPS-Harris Poll throughout 2017.

The Harvard CAPS-Harris Poll survey is an online sample drawn from the Harris Panel and weighted to reflect known demographics. As a representative online sample, it does not report a probability confidence interval.