What 3 past presidents did when they were subpoenaed, and what could happen if Mueller tries to make Trump testify

Thomas Jefferson was subpoenaed in 1807.

Jefferson became the first sitting president to be subpoenaed in 1807 in the trial of his Vice President Aaron Burr, who was accused of committing treason by planning a military invasion of Mexico.

In granting the prosecution's request to subpoena Jefferson to testify in court, then-trial judge and future Supreme Court Justice John Marshall wrote, "it is not known ever to have been doubted but that the chief magistrate of a state might be served with a subpoena."

Jefferson failed to comply with the subpoena and did not appear in court, citing a logistical inability to travel from Washington, DC to the location of the trial of Richmond, Virginia.

In a letter to one of prosecutors in the case, he wrote that his absence from the White House to testify “would leave the nation without an executive branch."

He did, however, produce certain documents requested by the court, and offered to be questioned in Washington. His lack of compliance with the order to testify in Richmond was never legally challenged.

Source: The New York Times

Richard Nixon was subpoenaed in 1974.

In 1973, Nixon was served with a federal subpoena to provide a trove of tapes and other materials relating to former White House staff who had been indicted in the Watergate scandal.

The president was listed as un-indicted co-conspirator in the grand jury indictment of the six people charged as part of Watergate, and the House of Representatives had begun impeachment proceedings.

Nixon's lawyer challenged the constitutionality of the subpoena, citing the executive privileges laid out in Article II of the US constitution. The matter went all the way up to the US Supreme Court, and resulted in a landmark case, US v. Nixon.

In a 8-0 decision, the court, led by Chief Justice Warren Burger, ruled against Nixon, ordering him to turn over the tapes and setting crucial legal precedent. Notably, Nixon was able to bring his case directly to the court without first being held in contempt.

The majority opinion acknowledged the existence of executive privilege, but dismissed the concept that the president is entitled to "absolute, unqualified Presidential privilege of immunity from judicial process under all circumstances."

Sixteen days after the court's decision, Nixon resigned from office before the issue of whether a sitting president could be compelled to testify before a grand jury could be tested in court.

Sources: Washington Post, Cornell Law School

Bill Clinton was subpoenaed in 1998.

In July 1998, independent counsel Ken Starr served Clinton with a subpoena to testify before a grand jury, as part of the Justice Department's investigation into his affair with White House intern Monica Lewinsky.

Clinton was already battling a civil suit from Paula Jones, an Arkansas state employee who accused him of sexual harassment. In the landmark case, Clinton v. Jones, in 1997, the Supreme Court ruled that presidents cannot claim immunity from civil litigation if the accusations were from before they took office.

The president struck a deal to testify voluntarily, prompting Starr to withdraw the subpoena.

On August 17, he gave four hours of testimony before a grand jury, and later delivered a televised address to the American people in which he admitted to his infidelity — and to his previous public lies about it, including his famous "I did not have sexual relations with that woman" speech.

"Indeed, I did have a relationship with Miss Lewinsky that was not appropriate," Clinton told the grand jury. "In fact, it was wrong. It constituted a critical lapse in judgment and a personal failure on my part for which I am solely and completely responsible."

The House of Representatives voted to impeach Clinton in December 1998 on charges of "high crimes and misdemeanors," specifically perjury and obstruction of justice. The Senate later acquitted him on both charges in January 1999.

Sources: Justia, Business Insider, TIME

What could happen if Trump were subpoenaed to testify before a grand jury?

If Mueller ends up subpoenaing Trump to testify before a grand jury, Giuliani said his legal team has a plan.

They would invoke the executive privileges outlined in Article II of the US Constitution, as well as cite Clinton-era Justice Department guidelines that instruct federal prosecutors not to indict a sitting president, which Mueller has indicated he will follow.

Roland Riopelle, a former assistant US attorney and criminal defense lawyer, told Business Insider he thought it was highly unlikely for a US District Court or the Supreme Court to accept those arguments based on the precedent that US v. Nixon and Clinton v. Jones set.

"I simply don't believe that president Trump will somehow find a basis on which his case should be treated any differently than Richard Nixon's or Bill Clinton's," Riopelle said. "If he gets subpoenaed, I believe the court will issue an order for him to appear before the grand jury."

Constitutional law experts Steve Vladeck and Benjamin Wittes agreed, writing in a May Lawfare article that while the president's legal team could make a case against it, "Mueller would probably prevail if and when a battle over a grand-jury subpoena makes its way into court."

"It’s hard to see how the courts could contend that the president must answer a civil complaint from Paula Jones but then contend that he need not answer a criminal investigative subpoena from a grand jury," they argued.

If Trump refuses to follow a court order to comply with the subpoena, Riopelle says it would be the first time a sitting president was held in contempt of court since Clinton in 1999, and could result in historically unprecedented chaos.

"We've never had an executive refuse to do what the highest court in the land ordered him to do," he said, adding it would lead to a "true, all-out constitutional crisis where there is one branch of government that is not functioning."

Sources: Business Insider, Lawfare, Washington Post