President Donald Trump declared Wednesday that he and his administration will battle House Democrats on all legal fronts after the special counsel's Russia report, refusing to cooperate with subpoenas and appealing to the Supreme Court if Congress tries to impeach him.

Trump, seething as Democrats ramp up their probes after Robert Mueller's Russia investigation, said he "thought after two years we'd be finished with it."

"I say it's enough," Trump told reporters on the White House's lawn as he left for an event in Atlanta, accusing the Democrats of using investigations for their electoral advantage in 2020.

"The only way they can luck out is by constantly going after me on nonsense. But they should be really focused on legislation, not the things ... this has been litigated, just so you understand, this has been litigated for the last two years, almost since I got into office."

Trump said his administration would be "fighting all the subpoenas."

One congressional subpoena the administration is expected to resist calls for an appearance by Don McGahn, the former White House counsel who cooperated with Mueller. And the White House is pushing back on other fronts, including House Democratic efforts to obtain Trump's tax returns and his business' financial records.

But Trump's strategy for fighting impeachment at the Supreme Court could run into a roadblock: The high court itself said in 1993 that the framers of the U.S. Constitution didn't intend for the courts to have the power to review impeachment proceedings. The Supreme Court ruled that impeachment and removal from office is Congress' duty alone.