Story by the Associated Press; curated by Oliver Darcy.

WASHINGTON (AP) — The White House is defying a congressional subpoena by keeping a top political aide to President Barack Obama from testifying at a hearing Wednesday.

The White House is arguing that Obama adviser David Simas (SEE’-muhs) is immune from subpoena by the House Oversight Committee in its investigation into the political office that he directs.

The White House plans to defy a congressional subpoena by keeping a top aide to President Barack Obama from testifying at a Wednesday hearing. (Image source: Shutterstock)

The White House plans to defy a congressional subpoena by keeping a top aide to President Barack Obama from testifying at a Wednesday hearing. (Image source: Shutterstock)

White House counsel Neil Eggleston says in a letter to Oversight Chairman Darrell Issa (EYE’-suh) that the Simas subpoena threatens the constitutional separation of powers.

White House lawyers spent an hour and 15 minutes Tuesday briefing the committee’s staff behind closed doors on the political office’s efforts to comply with federal law. But Issa says the committee still has questions he wants Simas to answer publicly.