The White House pushed back against Senate Democrats’ criticism that the Trump administration has declined to appoint commissioners to key regulatory agencies, a dispute that has emerged as a hurdle in lawmakers’ efforts to advance a landmark cryptocurrency bill.

On Thursday, White House officials sent a letter to Senate Majority Leader John Thune and Senate Minority Leader Charles Schumer, saying they wanted to "set the record straight."

"Democrats have obstructed every civilian nominee, but President Trump has still nominated Democrats to key positions," they said, citing Democratic nominations to the International Trade Commission and re-nominations to the National Labor Relations Board, among others.

The letter was signed by Director of Presidential Personnel Dan Scavino and Director of Legislative Affairs James Braid.

The debate over Trump’s appointments has drawn particular attention to the Commodity Futures Trading Commission, which could play a central role in overseeing digital assets if Congress passes the broader crypto market structure legislation known as the Clarity Act.

Currently, there is just one commissioner out of five spots, Republican Chair Michael Selig leading the agency. Lawmakers have pressed Trump to appoint CFTC commissioners to support the Clarity Act.

On Thursday, the White House said it sought Democratic names to lead the Securities and Exchange Commission and the CFTC, but didn't hear back.

Schumer's office did not immediately respond to a request for comment.

The White House officials also briefly cited a Supreme Court case ruling made last week in the letter. The case, Trump v. Slaughter, expanded President Trump's authority to remove leaders of many independent federal agencies.

"... these criticisms were answered by the recent Supreme Court ruling," the officials wrote.