Complicating the matter for senators is the Trump campaign’s decision to not engage, so far, in the traditional transition process, having declined to sign agreements with the federal government that would launch FBI background checks of nominees, among other standard steps before confirmation hearings.

Trump’s Cabinet picks are posing the biggest early test for Congress. While Trump’s choice of Sen. Marco Rubio, R-Fla., for secretary of state is expected to have somewhat broad support, including from Democrats, others like Kennedy, Tulsi Gabbard for director of national intelligence and Pete Hegseth as defense secretary are raising more scrutiny.