WASHINGTON (Reuters) - A U.S. judge on Monday dismissed a lawsuit brought by former White House aide Charles Kupperman seeking guidance on whether he needed to comply with a congressional subpoena in the impeachment inquiry into President Donald Trump.

U.S. District Judge Richard Leon in Washington said Kupperman’s lawsuit was “moot” because a U.S. House of Representatives committee withdrew a subpoena seeking his testimony.

In October, House investigators issued a subpoena to Kupperman for his testimony in their investigation into allegations that Trump improperly withheld security money as leverage to pressure Ukraine to investigate political rival Joe Biden.

Kupperman, a former deputy to ousted national security adviser John Bolton, did not appear for a scheduled deposition and House investigators eventually withdrew their subpoena to avoid a delay in the impeachment proceedings.