WASHINGTON — House Democrats slapped the White House with a subpoena for documents in their impeachment inquiry into President Trump’s Ukraine scandal on Friday.

Democrats are seeking documents and communications related to whether Trump pressured Ukraine to investigate his 2020 rival Joe Biden, in a scandal that has consumed Washington and thrown up new developments daily since bursting into public view in September.

“The White House has refused to engage with—or even respond to—multiple requests for documents from our Committees on a voluntary basis,” the chairmen of three House committees wrote in a joint letter accompanying the subpoena. “After nearly a month of stonewalling, it appears clear that the President has chosen the path of defiance, obstruction, and cover-up.”

Friday’s subpoena makes good on a threat from Democratic leaders earlier in the week, and follows several recent subpoenas directed at high-ranking officials and confidantes in Trump’s administration and inner circle, including Rudy Giuliani and Mike Pompeo.

Trump, meanwhile, has raised a broad blockade of Congressional requests for documents and witnesses, and tied up their subpoenas in lengthy court challenges that could outlast his presidency.

But Democrats’ impeachment inquiry could lend their subpoenas additional legal firepower, persuading judges that their Constitutional authority to conduct impeachment proceedings should override any defense he can raise, legal experts say.

The new White House subpoena set a deadline for compliance of Oct. 18.