WASHINGTON — The White House fired a warning shot Wednesday to Democrats threatening to investigate the administration once they take control of Congress in January.

“The administration will not be extorted and will not be cowed,” White House Counsel Will Scharf wrote to incoming House Oversight Chairman Rep. Robert Garcia, D-Calif.

In the missive, Scharf outlined the “limits” the Constitution places on congressional investigations and subpoenas, noting they can only be used for legislative purposes rather than “criminal persecution.”

Democrats have threatened to fire off a plethora of subpoenas targeting administration officials and the first family, with some newly minted lawmakers hinting that charges could follow.

Scharf’s letter is a sign of the aggressive defense the White House is expected to mount under the direction of new Chief of Staff Stephen Miller.

“Threats to executive branch officials designed to deter them from public service, or process designed merely to abuse or instill fear in the recipient may cross the line into blatant criminality,” Scharf wrote.

“And issuing unlawful subpoenas with the intention of depriving citizens of their constitutional rights and privileges may warrant further investigation.”