Given the amount of high-profile legal intrigue surrounding the House Democrats' impeachment inquiry into President Donald Trump, it was no surprise that Robert Luskin would get involved somehow.

A partner in Paul Hastings' Washington, D.C., office, Luskin is representing Gordon Sondland, the U.S. ambassador to the European Union, who was scheduled to be deposed by members of the House Intelligence, Foreign Affairs and Oversight committees.

Luskin, however, delivered the message early Tuesday that the State Department was blocking Sondland's testimony.

"As the sitting U.S. Ambassador to the EU and employee of the State Department, Ambassador Sondland is required to follow the Department's direction," Luskin said in a statement. "Ambassador Sondland is profoundly disappointed that he will not be able to testify today. Ambassador Sondland traveled to Washington from Brussels in order to prepare for his testimony and to be available to answer the Committee's questions."

By midday Tuesday, the chairmen of the House Foreign Affairs, Intelligence, and Oversight committees had released a joint statement saying they will be subpoenaing Sondland for both his testimony and documents.

Luskin told The National Law Journal that he and his partner in Paul Hastings' investigations and white-collar defense practice, Kwame Manley, began representing Sondland about 10 days ago. Luskin said he is not currently representing anyone else who is being scrutinized in the House Democrats' impeachment inquiry.

Luskin said he began representing Sondland because he felt comfortable with the ambassador's willingness to be candid and truthful.

Luskin has long been a known quantity in D.C. circles. His clients have included Karl Rove—the former George W. Bush senior adviser who was scrutinized as part of the special investigation into the leak of Valerie Plame's identity as a covert CIA official—and Nicholas Marsh, a former federal prosecutor who committed suicide in 2010 after he bungled a corruption trial against Sen. Ted Stevens of Alaska.

He also had a role in the special counsel investigation conducted by Robert Mueller, representing Cambridge professor and FBI informant Stefan Halper, who was in contact with a Trump campaign official during the 2016 presidential election.

Luskin has also represented the ex-Navy SEAL who took part in the raid that killed Osama bin Laden in his legal struggles with the U.S. government. And he's represented at least two members of Congress—Tom Feeney and Vern Buchanan, both Republicans from Florida—when they have been investigated by the U.S. Justice Department.

Luskin joined Paul Hastings in 2015, jumping ship from Squire Patton Boggs with a number of other colleagues and his alleged $20 million book of business.