On April 2, the committee voted across party lines to authorize a subpoena for Kline, the former White House personnel security director who allegedly overruled experts on dozens of controversial security clearances, prompting a House investigation into the matter.

In another letter, Kline’s attorney, Robert Driscoll, said that with “two masters from two equal branches of government, [Kline] will follow the instructions of the one that employs him.”

Kline became a subject of Cummings’ investigation after whistleblower Tricia Newbold, a current White House employee, came forward with a list of 25 instances that Kline had approved top-secret security clearance despite objections from intelligence experts.

The most high-profile of those controversial clearances Kline reportedly ordered went to Trump’s son-in-law Jared Kushner, who the FBI was concerned could be an easy target of foreign influence.

This is only the latest instance of the White House refusing to comply with the House investigation into the matter, which came to light last year when it was revealed that dozens of staffers awaiting final security clearance were using temporary approvals to access highly sensitive government information in the meantime.