On Monday, President Donald Trump interfered for the first time with the House's impeachment inquiry into him by blocking Gordon Sondland, the ambassador to the European Union, from speaking with investigators.

John King, CNN’s Chief National Political Correspondent, said that while a federal court could overrule Trump, it could take months for the case to work its way through the court system.

“Subpoenas, as we learned from the Mueller inquiry days, can take days, if not months, to resolve in the federal courts,” King said during an interview with Boston Public Radio on Tuesday.

Sondland’s testimony is not necessary for the House to move forward with an impeachment vote, but King said that testimony from individuals such as Sondland could be critical to convincing some voters that the president abused his power, and the inquiry is more than a political tactic.

“The issue though ... is if you’re the Democrats and you’re trying to convince independents and Trump voters that the president abused his power, you need these ... witnesses to lay out the facts, and the president’s team is saying right now, ‘You’re not going to get them,’” King said.