This was a vote on a motion requesting absent senators to report to the Senate floor, thereby allowing the Senate to proceed with its normal business.
Specifically, the Senate had been in a “quorum call,” which technically requires the Senate clerk to determine if a majority of senators are present. In reality, quorum calls simply halt all legislative business while senators negotiate with one another. Generally, the clerk reads the names of all senators until a member of the Senate asks that the quorum call be “dispensed with”—or ended. However, ending quorum calls requires the “unanimous consent” of the Senate—literally, the support of all senators. Normally, quorum calls are ended without objection. In this case, however, Sen. Ron Johnson (R-WI) objected to dispensing with the quorum call. Since a majority of senators were not present when Johnson objected, Sen. Majority Leader Harry Reid (D-NV) was forced to request the presence of absent senators—which would provide a quorum and thus allow the quorum call to end. This vote was on Reid’s motion to request the presence of absent senators. (Such motions are also known as “live quorums.”)
Johnson objected to ending the quorum call because he had vowed to block all unanimous consent requests until Senate Democrats (who controlled the chamber) brought up a budget bill to reduce the national debt. Talking Points Memo reported:
Sen. Ron Johnson (R-WI) ground the Senate to a halt on Tuesday, threatening to block "business as usual" until Democrats submit a budget.
Johnson began his broadside by objecting to a quorum call, blocking the Senate from proceeding with a vote. Quorum calls, like many basic Senate procedures, are approved by unanimous consent and Johnson threatened in a floor speech to wreak havoc on these uncontroversial motions.
"Business as usual is bankrupting America," he said in a floor speech. "It must stop."
Elaborating on his scheme, Johnson warned that "unless we receive some assurance from the Democrat leadership that we will actually start addressing our budget out in the open, in the bright light of day, I will begin to object. I will begin to withhold my consent."
The Senate agreed to the motion requesting the presence of absent senators by a vote of 44-40. All 42 Democrats present and 2 Republicans voted “yea.” 40 Republicans voted “nay.” Since a quorum (majority of senators) was present, the Senate was able to proceed with its normal business.