President Donald Trump's sweeping assertions of executive power during his first weeks back in office appear headed toward U.S. Supreme Court showdowns, but it remains an open question whether or how much the justices might act to check his authority.

An administration lawyer said a Tennessee law barring some medical treatments for transgender youths is constitutional and urged the justices to say so.

The president fired inspectors general without providing Congress the legally required notification and list of reasons for dismissal. Some in Trump's orbit have previously said the president should actively confront the judiciary.