WASHINGTON (Reuters) – A deadline for the U.S. Internal Revenue Service to turn President Donald Trump’s tax returns over to a congressional tax oversight committee expired on Tuesday without lawmakers receiving the documents, a committee aide said.

The outcome, which was widely expected, could prompt Democrats who control the tax-writing House Ways and Means Committee to subpoena the documents, as an opening salvo in what many expect to be a lengthy court battle that might have to be settled by the U.S. Supreme Court.

(Reporting by David Morgan; Editing by Lisa Shumaker and Peter Cooney)