WASHINGTON—Republican senators are making a mad dash to pass the GOP tax-and-spending megabill and send it to President Trump’s desk by July 4.Senate Republicans cleared the first procedural hurdle late Saturday by a 51-49 vote.

The wildly unpopular “Big Beautiful” reconciliation package has encountered possibly existential challenges, though Senate Republicans still hope to bring it to the floor this weekend. Senate Republicans rewrote key provisions of it after Parliamentarian Elizabeth MacDonough rejected many of Republicans’ proposed Medicaid cuts,