The White House is threatening a criminal investigation into congressional Democrats over their plans to scrutinize President Donald Trump’s administration, escalating tensions before the party takes control of the House in January.

In a letter to incoming House Oversight Committee Chair Robert Garcia, White House counsel Will Scharf alleged that Democrats’ public promises to investigate the president and his allies could exceed constitutional limits and potentially amount to illegal threats.

The letter, dated Monday and made public Wednesday, says the White House is “monitoring the abusive and capricious threats that are now proliferating from Democrat legislators who seek to abuse the legislative process to intimidate and to interfere with the lawful functioning of government.”

Scharf cited statements by Garcia and other Democrats in arguing that their planned investigations lack a legitimate legislative purpose. He characterized the comments as threats “designed to deter them from public service, or process designed merely to abuse or instill fear.”

The White House lawyer warned that such conduct could rise to the level of “blatant criminality” and prompt an executive branch investigation into Congress.

The warning closely follows social media posts by Trump suggesting that Democrats could face criminal consequences for their aggressive oversight posture. The intervention by the White House counsel is a departure from typical practice, in which the Justice Department serves as the administration’s principal point of contact with Congress on oversight matters.

The dispute centers on the legal requirement that congressional subpoenas have a legislative purpose and not be used solely to harass or intimidate. But courts have long given substantial deference to congressional investigators and generally declined to examine individual lawmakers’ subjective motives when committees take action.

Democrats are preparing an extensive oversight push when they assume the House majority in January, setting up a confrontation with an administration that has already signaled its willingness to challenge their investigations.

A spokesperson for Garcia did not immediately respond to a request for comment.