The Senate voted against ending debate on the Democratic leadership’s oil markets speculation bill on Friday morning. On a 50-43 vote, Republicans upheld their promise to prevent the Senate from moving beyond consideration of the speculation bill. GOP lawmakers criticized Majority Leader Harry Reid (D-Nev.) for prohibiting them from offering amendments to the bill. In what is likely the last pre-recess bill addressing the energy crisis, Reid filled the amendment tree — a parliamentary move that prevents amendments from being offered. The Nevada Democrat said Republicans were “not serious” about passing energy legislation All week, Senate leaders have been in a political standoff over amendments to the speculation bill. According to Reid, Republicans wanted to offer up to 28 amendments, even though Congress leaves for its summer break in one week. Republicans maintain that they will not allow Democrats to move to any other bill unrelated to reducing gasoline prices. That promise will not cause any problems for a housing bill, which is receiving special privilege under Senate rules, but may impede other Democratic priorities such as a low-income home heating assistance bill and a bipartisan package blocked by Sen. Tom Coburn (R-Okla).