President Donald Trump waves good-bye as he boards Air Force 1. (Photo: White House)

Sixteen conservative lawyers from major U.S. law firms, law schools and think tanks on Thursday asserted their support for an "expeditious" impeachment investigation, arguing in a new public statement that President Donald Trump has abused the office of the presidency.

The letter, published online by the conservative lawyers' group Checks & Balances, declared based on recent events involving Trump's efforts to enlist foreign help to investigate political rivals that "the president is abusing the office of the presidency for personal political objectives."

"We believe the acts revealed publicly over the past several weeks are fundamentally incompatible with the president's oath of office, his duties as commander in chief, and his constitutional obligation to 'take care that the laws be faithfully executed,'" the Checks & Balances letter said. "These acts, based on what has been revealed to date, are a legitimate basis for an expeditious impeachment investigation, vote in the House of Representatives and potential trial in the Senate."

Trump has dismissed claims that his call with the Ukraine president in July violated any law, and the White House counsel's office this week declared it would not cooperate with a House impeachment inquiry that was derided as "constitutionally defective." White House Counsel Pat Cipollone's eight-page letter to the House accused Democrats of using impeachment to try to negate the results of the 2016 election.

Many of the signatories on Thursday's letter have been outspoken critics of the Trump administration or have signed earlier Checks & Balances letters that criticized Trump's conduct as president. The group formed last year as part of an effort among conservative lawyers to speak out more visibly against perceived transgressions on the rule of law by the Trump administration.

The signatories on the latest letter included prominent Trump critic George Conway III, of counsel to Wachtell, Lipton, Rosen & Katz; Sidley Austin partner Peter Keisler, a former acting U.S. attorney general; Kirkland & Ellis partner Andrew Sagor, a former State Department official; Marisa Maleck, a senior associate at King & Spalding and former clerk to Justice Clarence Thomas; Trevor Potter, a Caplin & Drysdale partner and former chairman of the Federal Election Commission; Jaime Sneider, a Boies Schiller Flexner partner and former deputy associate director of communications at the White House; Carrie Cordero, general counsel to the Center for a New American Security; and Donald Ayer, a former Justice Department lawyer and retired Jones Day partner.

Peter Keisler. (Photo: Diego M. Radzinschi/ALM)

"I am disgusted by the conduct of Republican senators who pose as reputable people, but shamelessly hide under rocks instead of calling out the president's horrendous behavior as the gross misconduct that they know it to be," Ayer told The Washington Post.

The law professors who signed the letter include Harvard Law School professor Charles Fried, a former Reagan administration U.S. solicitor general; Orin Kerr of University of California Berkeley School of Law; J.W. Verret of George Mason University Antonin Scalia School of Law; and Jonathan Adler of Case Western Reserve University School of Law.

Thursday's letter came with a disclaimer, repeated on earlier statements, that said "each of us speaks and acts solely in our individual capacities, and our views should not be attributed to any organization with which we may be affiliated."

Arnold & Porter's John Bellinger III, who has signed earlier Checks & Balances statements, did not appear on Thursday's open letter. Bellinger told the National Law Journal in an email: "I certainly share the sentiments of my colleagues but I am representing one of the State Department officials in the Ukraine investigation and thought it better not to comment about the matter independently."

Bellinger, a former State Department legal adviser who now heads Arnold & Porter's global law and public policy practice, told the New York Times last year: "Conservative lawyers are not doing enough to protect constitutional principles that are being undermined by the statements and actions of this president."

The signatories on Thursday's letter said Trump's attempts to enlist the help of Ukraine and China to investigate Joe Biden, the Democratic presidential hopeful, "undermine the integrity of our elections, endanger global U.S. security and defense partnerships, and threaten our democracy."

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