Senate Democrats launched a rare, all-night debate on Monday that was scheduled to last past midnight, to protest Senate Republicans’ opposition to legislation that would require companies, unions and other groups to report their campaign spending.

Democrats warned that they would hold a “midnight vigil” if Republicans blocked the vote on their bill, and they began shortly before 7 p.m., just minutes after GOP did in fact unanimously oppose the bill. Democrats were hoping to end debate on the bill, which needed 60 votes, but the vote failed 51-44.

Democrats immediately lined up more than a dozen speakers, and planned to debate the bill until 1 a.m., and then take up the issue again Tuesday morning.