As a woman of principle in a hyperpartisan era, Sen. Susan Collins has sometimes been subjected to extraordinary pressure because of her defense of the Senate’s deliberative role. In this she shares a thing or two with Sens. Margaret Chase Smith and John McCain. Smith, whom Collins claims as her role model, and McCain, her avowed mentor, were loyalists with a difference: Each had a moral compass that occasionally lifted our country, too. Collins aspires to follow their example. As she considers her vote on Brett Kavanaugh, her aspiration will be tested as never before.

The charge of attempted sexual assault made against Kavanaugh is obviously deeply troubling, despite his denial. This is not the only issue that warrants slowing the rush to confirm him to the Supreme Court.

Brett Kavanaugh on the third day of his Senate Judiciary Committee confirmation hearing. Associated Press/Jacquelyn Martin

Kavanaugh is well to Collins’ right, but policy differences may ultimately matter less to her than principles protecting American democracy. Two of these would be jeopardized by his confirmation: the separation of powers and the Senate’s role in screening a nominee.

Kavanaugh has written that sitting presidents should be relieved of the “burdens of ordinary citizenship” including the “time-consuming and distracting” tasks answering to “a criminal investigation.” Perversely, such immunity could shield a president from accountability for criminal acts that may have led to the presidency, and its alleged immunity, in the first place.

For a president facing growing legal liability, Kavanaugh’s immunity theory is too convenient, creating the appearance of a powerful conflict of interest in favor of his new patron. Yet Kavanaugh has not agreed to recuse himself from criminal or civil investigations relating to the president. Nevertheless, Kavanaugh’s view that serving presidents should be beyond the reach of judicial action offends the core value that a president is not a king who is above the law and the Constitution’s dictate that the three branches of government are co-equal. It likely offends Sen. Collins, too.

There is also reason to believe that Kavanaugh has materially misled the Senate in his testimony under oath in 2004 and 2006 and again this month.

Between 2001 and 2003, Kavanaugh played a central role in the judicial confirmation process for the George W. Bush White House. Recently released emails show that during that time, a Republican Senate lawyer, Manuel Miranda, pilfered over 4,600 computer files on Bush judicial nominees from Democratic senators. Kavanaugh was questioned about the materials while under oath in 2004 and in 2006, always answering that he never received such materials or anything that appeared to have been created by Democratic committee staff.

An April 2004 exchange between Sen. Orrin Hatch and Kavanaugh was typical:

Hatch: “Did Mr. Miranda ever share, reference or provide you with any documents that appeared to you to have been drafted or prepared by Democratic staff members of the Senate Judiciary Committee?”

Kavanaugh: “No. I was not aware of that matter until I learned of it in the media last year.”

Hatch repeated the question, but more narrowly worded: “… any information you believed or were led to believe was obtained or derived from Democratic files?” Kavanaugh’s answer was the same.

He restated his categorical denials repeatedly during testimony in 2004 and 2006. At the time, committee Democrats lacked grounds to challenge them, but this month was different: Public records from the Bush White House contradicted Kavanaugh’s false claims of ignorance.

An email from Miranda to Kavanaugh — described by Sen. Patrick Leahy on Sept. 5 — was typical. It contained the draft text of a January 2003 letter from committee Democrats to then-Senate Minority Leader Tom Daschle, setting out a confidential negotiating position.

Confronted by Leahy in open session, Kavanaugh tried to divert the discussion, claiming it was common to receive such information, even though the White House and the Democrats were in intense opposition over judicial nominees. Another email from Miranda to Kavanaugh pasted in research obviously created by Democratic staffers. Yet another disclosed the author and sensitive content of a highly “confidential” letter that Miranda said was restricted to Democratic counsel..

Armed with documentary evidence, on Sept. 5 and 6 Democrats exposed more apparent Kavanaugh falsehoods: concerning his relationship with Miranda, talking points, internal communications and more.

The first canon in the Code of Judicial Ethics enjoins judges to avoid actions that “would create in reasonable minds” a perception of dishonesty. Kavanaugh’s conduct before the Senate Judiciary Committee would seem to fit what the canon proscribes.

Susan Collins’ record shows a reasonable mind. The question is whether it will guide her.

Peter Fromuth of Yarmouth is a lawyer who served in senior State Department posts in the Clinton and George W. Bush administrations.