One Republican, John Fleming, has already jumped in to challenge Cassidy for the party’s Senate nomination next year. Fleming, who served four terms representing a western Louisiana district in the House, cited Cassidy’s impeachment vote in announcing his bid in December.

The Senate Finance Committee is voting on whether or not to move forward with Robert F. Kennedy Jr.'s confirmation.

The Louisiana Republican, who led a hepatitis B vaccination campaign before entering politics, has expressed concerns about Robert F. Kennedy Jr's views on vaccines.