Robert F. Kennedy's nomination will put Republican lawmakers' loyalty to the test, as the former Democrat holds a range of unorthodox positions that could alienate both conservatives and liberals.

Three of President Donald Trump’s cabinet picks prepared to face skepticism and intense grilling from Democratic senators Thursday.

Sen. Bill Cassidy, the top Republican on the Senate Committee on Health, Education, Labor and Pensions, concluded Thursday's hearing by saying he was "struggling" with the nomination due to Kennedy's vaccine positions. Kennedy notably refused to say vaccines don't cause autism as he faced pointed question from lawmakers.