WASHINGTON (Reuters) - U.S. Senate Republicans will gather behind closed doors on Wednesday to pick their next leader in the face of a public pressure campaign by supporters of President-elect Donald Trump who favor the long-shot bid of a hardline Trump loyalist.

Who senators choose, and whether Trump ultimately endorses a candidate in the final hours, could set the tone for Trump’s attempts to assert control over the legislative branch.

Following the election, Republicans will control the Senate with a 53 to 47 majority, but one question remains -- who will become the new Senate majority leader? Outgoing leader Mitch McConnell will remain in Congress but will step aside as the longest serving party leader in history.