WASHINGTON (AP) — Republican senators will gather behind closed doors Wednesday to decide who will replace longtime Senate leader Mitch McConnell and lead their new majority next year — a decision that could shape the future of the Senate, and the party, as Donald Trump reclaims the presidency.

It was the first seriously contested Senate Republican leadership election in decades. Three senators were competing to succeed longtime GOP leader Mitch McConnell of Kentucky, when he steps down from the post at the beginning of next year and Republicans take back the Senate majority.

The election of Republican John Thune of South Dakota as Senate majority leader tasks a key ally of Mitch McConnell with shepherding the agenda of President-elect Donald Trump through Congress.

Sen. John Thune of South Dakota is one of the most powerful people in Washington that folks outside D.C. have never heard of.

John Thune, 63, defeated Sens. John Cornyn and Rick Scott in the secret-ballot vote to succeed Mitch McConnell as Senate majority leader.

An army of online pro-Trump voices is trying to boost underdog Rick Scott for Senate Republican leader over two Mitch McConnell deputies, John Thune and John Cornyn.

Senate Republicans returned to Washington for the first time since they secured the Senate majority to determine who will be the new party leader in the chamber.

House Republicans are picking which leaders will represent them in the new Trump administration government next year.

President-elect Donald Trump will meet with House Republicans on Wednesday as the party awaits the prospect of scoring a trifecta in Washington with control of both chambers of Congress and the White House.