The Senate starts at 2 p.m. and at 5:30 p.m. it will vote to end debate on the nomination of Keith Harper to be a U.S. representative to the United Nations Human Rights Council.

Some Senate Republicans have opposed Harper’s nomination; he was a former fundraiser for President Obama.

The Senate Foreign Relations Committee cleared Harper’s nomination on a party-line vote in February.

Harper, a member of the Cherokee Nation in Oklahoma, was a top bundler for Obama’s presidential campaign in 2008 and a member of the administration’s transition team. He would be the first member of a federally recognized tribe to serve in an ambassador role.

Republicans are forcing Democrats to vote to end debate before final confirmation, but because Democrats have 55 votes in the Senate, confirmation is nearly certain. Last year, Senate Democrats used the “nuclear option” to unilaterally change the filibuster rules so that a simple majority can advance most nominations instead of the previously needed 60 votes.

Harper’s final confirmation is expected Tuesday.

The House is not in session.

— Jasmine Sachar contributed to this article.