This was ostensibly a vote on a motion to waive the Senate's budget rules with respect to an amendment by Sen. Tom Coburn (R-OK) allowing veterans deemed to be “mentally incompetent” to possess firearms. (Under current law, mental health background checks can prevent individuals from obtaining guns.) The measure Coburn sought to amend was a “companion bill” making a number of changes to health care reform legislation already signed into law by President Obama. The underlying context was that Republicans were trying to attach amendments to the companion bill in order to send it back the House, where it had passed by a narrow margin. CNN reported that Republicans had chosen to offer a slew of amendments in order to “undermine the measure,” while the Associated Press characterized the amendments as “a final drive to thwart President Barack Obama's health care remake.”

Coburn urged support for his amendment: “140,000 of our troops have lost their second amendment rights as they go through the VA hospital system. They are not a danger to themselves or anyone else….”

Sen. Max Baucus (D-MT) argued the amendment was irrelevant to health care: “All of us have a strong belief in the second amendment to our Constitution. But whatever you think about second amendment rights and the application of the second amendment, whatever you think about veterans and the relationship to questions of competency, I think we all should agree that neither what anybody thinks about second amendment rights or what veterans' relations should be to that should be in this bill. This is a health care bill.” Baucus also contended the amendment violated the Senate’s budget rules because gun control “is not [under] the jurisdiction of the relevant committees.” In other words, the committees responsible for drafting the reconciliation bill (the Finance Committee and the Health, Education, and Labor Committee) did not have authority over gun control legislation. Thus, Baucus argued, the amendment violated the Senate’s budget reconciliation rules. Coburn then made a motion to waive those rules. Motions to waive budget rules require 60 votes for passage.

After the House and Senate both passed their respective health care reform bills, the two chambers had intended to reconcile those two bills into a final package. After the House and Senate passed that final package, it would have been sent to President Obama, who would have signed it into law. Sen. Scott Brown (R-MA), however, won a special election to replace the late Sen. Ted Kennedy (D-MA) before the final health care bill could be brought up for a vote. Brown's victory gave Republicans 41 votes in the Senate, leaving Democrats with 59 members – one vote short of the 60 votes they needed to defeat a unanimous Republican filibuster against the final health care bill. 

In order to pass comprehensive health care legislation without a 60-vote majority in the Senate, Democratic leaders devised a plan in which the House would pass the Senate health care bill (H.R. 3590), thereby enabling the president to sign it into law. The House would then pass a separate companion bill (H.R. 4872) to make changes to the Senate health measure under a process known as "budget reconciliation." Bills considered under budget reconciliation cannot be filibustered under Senate rules. This process allowed the House to make changes to Senate-passed health care legislation without sending the entire health bill back to the Senate, where it could have been filibustered indefinitely.   The companion bill incorporated changes to the Senate health care legislation desired by House Democrats. The House passed the companion measure, and sent it to the Senate, where Democratic leaders hoped to defeat all amendments -- thereby avoiding a second vote in the House on a substantively changed bill; a vote that Democrats might have lost given the already tight margin when it was voted on the previous week.

The Senate rejected the motion to waive its budget rules by a vote of 45-53. All 40 Republicans present and 5 Democrats voted “yea.” 53 Democrats voted “nay.” As a result, the Senate effectively rejected an amendment Democratic leaders feared could have torpedoed the entire companion health care measure and  would have allowed veterans deemed to be “mentally incompetent” to possess firearms.