The Democratic-controlled House Judiciary Committee is set to vote Wednesday to authorize subpoenas to obtain the full report on Russian meddling in the 2016 U.S. presidential election from special counsel Robert Mueller, as well as the testimonies of five former White House officials interviewed by the special counsel.

Lawmakers were expected to vote along party lines to authorize Committee Chairman Jerrold Nadler to subpoena documents and testimony from five former Trump aides, including former political advisor Steve Bannon and former White House Counsel Donald McGahn.

While Trump has left it to Attorney General William Barr to decide whether to release the complete report, the president is expected to assert what is known as executive privilege over some portions of records other congressional committees are seeking as part of their investigation of the administration. That has set the stage for a showdown between Democrats in Congress and the White House, raising the specter that the issue may ultimately end up before the U.S. Supreme Court.

But if the past is any indication, the coming battle is likely to be fought — and eventually settled — through political give and take between the executive and legislative branches of government rather than the courts, said Mark Rozell, dean of the Schar School of Policy and Government at George Mason University and author of an acclaimed book on executive privilege.

"Historically, I found in my studies on executive privilege that presidents and Congress have done a good job of engaging in a negotiating process and settling these matters because they both understood that they had a real incentive not to let this go into the courts and not to let these matters drag on," Rozell said.

Executive privilege

Executive privilege is the right of the president and his senior advisers to protect certain communications from disclosure to Congress and the courts. While the courts have long recognized that power, as well as Congress' authority to investigate the executive branch, they've been reluctant to decide disputes over access to records between the two branches of government.

"Courts have typically required the executive and the legislative branches to engage in a good faith back-and-forth accommodation process about the information before the court will ultimately decide the issue of whether certain documents or testimony are required to be provided to the Congress," said Margaret Taylor, a senior editor at the popular Lawfare legal blog and a fellow in governance studies at the Brookings Institution.

Short of serving a subpoena, Congress has other tools it can use to seek access to information from the executive branch, including the power of appropriation and the power to confirm senior administration officials, Taylor said.

"These are other tools that Congress can use to hasten … the provision of information from the executive branch to the Congress," Taylor said.

Congress' power to investigate

While not enshrined in the Constitution, Congress' power to investigate and obtain confidential information from the executive branch is "extremely broad" and has been recognized as essential to its legislative function, according to the Congressional Research Service.

To obtain information or testimony from executive branch officials, congressional committees initially submit a request. When that fails, Congress can resort to another means of compulsion: subpoenas.

Failure to comply with a congressional subpoena can lead to a vote by the full House or Senate holding the person in contempt of Congress and referring him or her to the Department of Justice for prosecution. If the Justice Department is unwilling to bring charges, Congress can seek a civil judgment from a federal court compelling the individual to respond.

With the power of executive privilege, presidents have wide latitude to refuse to fully comply with congressional subpoenas. While there is no consensus on the scope of executive privilege, Taylor said presidents have claimed executive privilege over several categories of information — sensitive or classified information; presidential deliberations with advisers; attorney-client communications; law enforcement investigations and national security matters.

"These claims of executive privilege aren't always successful," Taylor said. "Sometimes the president ends up waving the privilege and going ahead and sharing the information."

While presidents going back to Dwight Eisenhower in the 1950s have asserted executive privilege, previous presidents "exercised various forms of presidential secrecy that are consistent with what we today call executive privilege," Rozell said.

Past examples

But it was during the 1970s Watergate scandal that the concept became firmly established when the Nixon administration unsuccessfully fought a grand jury subpoena to turn over secret recordings of White House conversations between President Richard Nixon and his aides.

"The Supreme Court in that case said there is a principle of executive privilege, but it does not apply in this particular instance because there are allegations of wrongdoing, and criminal justice requires access to as much information as possible in order to get the facts," Rozell said.