If President Donald Trump interferes with special counsel Robert Mueller's inverstigation or fires him, what should Congress do? At least that's what he said two decades ago. During Kavanaugh's confirmation hearings, Trump's latest Supreme Court nominee refused to answer questions about issues of presidential power that could well be tested in the coming months. He declined to say whether he believes a president can pardon himself. Kavanaugh would not say whether a president can be compelled to respond to a subpoena.