How Donald Trump could speed up Robert Mueller's Russia investigation: Talk to him. Executive privilege claim is more political theater than legal firewall as Donald Trump tries to avoid a Robert Mueller interview on Russia. It's likely to fail.

Norman Eisen and Andrew M. Wright | Opinion contributors

Show Caption Hide Caption Michael Cohen says loyalty is first to family and country, not Trump Breaking his silence, President Trump's "bulldog" lawyer Michael Cohen, made it clear where his loyalty really lies. Nathan Rousseau Smith has the story.

"Finish it the hell up," Rep. Trey Gowdy said last week of special counsel Robert Mueller's investigation into Russian interference in the 2016 election. In truth, Mueller is moving rapidly and could go even faster if President Donald Trump would agree to talk to him.

He requested an interview with Trump more than six months ago and now reportedly has threatened a subpoena. All signs indicate a legal showdown ahead — and Mueller would very probably win it.

The president and his advisers have taken no apparent steps toward cooperation, instead purveying a smorgasbord of aggressive legal arguments with a heavy emphasis on a claim that “executive privilege” justifies a blanket refusal to testify. But despite the public bluster, calling Mueller on his subpoena bluff is a tenuous legal strategy, as we explain in a new report. The president would trigger a court battle that would likely delay but not ultimately prevent the special counsel from obtaining his testimony.

Executive privilege is an assertion of presidential authority to withhold information from a judicial or congressional proceeding in order to preserve executive branch confidentiality interests. Courts have long recognized executive privilege as a “weighty” and constitutionally grounded interest that advances the public interest in ensuring candid and thorough deliberations among the president and his close advisers.

At the same time, executive secrecy stands in stark tension with the information needs of others, including congressional oversight committees, grand juries and the public — and therefore it is not absolute. Given that the public needs both executive branch functionality and democratic transparency and accountability, courts employ a balancing test when evaluating executive privilege claims.

Compelling public interest in Trump testimony

In United States v. Nixon, the leading Supreme Court case involving a subpoena to the president in a criminal proceeding, the court weighed “the importance of the general privilege of confidentiality of presidential communications in performance of the president’s responsibilities against the inroads of such a privilege on the fair administration of criminal justice.”

Similarly, in cases involving congressional demands for presidential communications, courts recognize that neither the executive branch nor Congress has absolute authority and urge a process of accommodation.

This framework has resulted in important precedents for criminal and congressional investigators obtaining access to highly sensitive executive branch information.

For example, although Presidents Richard Nixon and Bill Clinton both invoked executive privilege to block White House evidence and testimony from reaching criminal inquiries, courts ultimately rejected both claims. The Supreme Court resolved Nixon's claim by directing the White House to turn over to the federal court the tapes subpoenaed by the special prosecutor. In Clinton's case, courts rejected executive and attorney-client privilege claims regarding grand jury testimony of two senior White House advisers sought by independent counsel Kenneth Starr.

More: Donald Trump's 'witch hunt' has evoked whining for more than a year now

Robert Mueller's Trump-Russia investigation is a year old. Too soon to 'wrap it up.'

Crossfire Hurricane: Pull back curtain on FBI's investigation of Donald Trump, Russia

White House advisers who have testified about official matters have included people serving as White House counsel, chief of staff to the vice president, White House chief of staff, White House deputy chief of staff and national security adviser. Congress and other investigators also have obtained access to highly sensitive White House documents, such as National Security Council staff notes on a phone conversation between Clinton and the Israeli prime minister; intelligence documents for President George W. Bush on Osama bin Laden’s intent to strike in the USA, and emails from national security officials concerning attacks on U.S. facilities in Benghazi, Libya, during the Obama administration.

In the Russia investigation, executive privilege will not spare Trump from submitting to questions from Mueller. The public interest in presidential testimony in this matter is compelling because it concerns issues central to a functional democratic system: foreign interference with national elections and any related obstruction of justice that violates the rule of law.

Political theater or legal firewall?

Mueller has a clear investigative need to get firsthand accounts from Trump about Russian contacts during the campaign and transition, and his state of mind regarding problematic acts he has taken to hamper the Russia investigation itself.

The special counsel has already indicted or obtained guilty pleas from 23 individuals and companies, including Trump's two leading campaign officials and his former top national security adviser for crimes that include conspiracy against America and lying to federal investigators.

Mueller and the American public need to understand whether the president was involved with activities implicated in these criminal proceedings. Surely, he deserves at least as much time as it took Gowdy to investigate the deaths of four Americans in Benghazi — a two-year undertaking that produced no charges.

Because courts expect the president to assert any executive privilege claims document by document or question by question, a blanket refusal to respond to Mueller's interview request won’t fly. The need to evaluate core issues in the obstruction of justice investigation, including the president’s removal of FBI Director James Comey and pretextual reasons offered for it, would weigh heavily against any blanket executive privilege claim.

If past is prologue, the president and his legal team will likely continue their modern-day “will he or won’t he” Hamlet act about appearing before Mueller in the Russia probe. As it relates to executive privilege, it’s more political theater than legal firewall.

At some point, the special counsel will call their bluff and subpoena the president. If he and his team try their performance in court, judges will almost surely ring down the curtain.

Norman Eisen, chair of Citizens for Responsibility and Ethics in Washington, was chief White House ethics lawyer in the Obama administration. Andrew M. Wright, an associate professor at Savannah Law School, served as associate White House counsel in the Obama administration and staff director of a congressional oversight subcommittee. Follow them on Twitter: @NormEisen and @AndyMcCanse