Washington (CNN) Republican Sen. Lindsey Graham, a close ally of President Donald Trump's on Capitol Hill, announced Friday that a resolution he introduced condemning the House impeachment inquiry process now has 50 co-sponsors in the Senate.

That number would give Republicans enough votes to reach a simple majority in the Senate if Vice President Mike Pence cast a tie-breaking vote in favor if it comes to the floor. If Senate Democrats were to filibuster, however, that would raise the threshold needed to 60 votes.

The resolution is critical of the way House Democrats are conducting the impeachment inquiry and calls on the House to hold a vote to initiate a formal inquiry.

It argues that the House is "denying President Trump basic fairness and due process accorded every American."

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