The filibuster occurred when Hagel, a Nebraska Republican, was unable to garner the 60 required votes to end debate and advance to a final confirmation vote. This marks the first time in history where a presidential cabinet nominee was postponed from cloture – the method of ending debate and calling for a vote.

“(The Senate) had the right in doing so,” Central Michigan University political science professor Thomas Stewart said. “It is the Senate’s role and responsibility to block consent if (senators) feel their questions are going unanswered.”

Hagel fell one vote short of receiving a confirmation vote. Though he received 58 votes in total, Senate Majority Leader Harry Reid voted nay at the last-minute for procedural purposes in order to ensure a continued nomination process.

Republicans stated various reasons as to why they temporarily blocked Hagel’s nomination.

Sen. John McCain, R-Ariz., said two days was an insufficient period of debate, while he and other Republicans believed Senate Democrats rushed them through the process. Many still had questions outstanding.

Senate Democrats, who outnumber Republicans 55-45, voted uniformly for Hagel, except for Reid. If Republicans had not filibustered Hagel’s nomination, the Senate would hold a simple majority vote to confirm him as Secretary of Defense.

Many Democrats, including Sen. Carl Levin, D-Mich., were frustrated by the proceedings

“There’s a suggestion there be a delay of eight days for something where people know how they’re going to vote now,” Levin told reporters following the filibuster. “(Defense Secretary Leon Panetta) wants to go home. You need somebody who is locked into the issues, not someone whose mind is on a walnut farm.”

Due to their leverage with the 60-vote threshold, Republicans called for the White House to release additional information on the Benghazi, Libya attacks that left four Americans dead. This prompted the reveal of documents that stated President Barack Obama did not talk with Libyan officials until the night after the attacks.

Though Panetta will, in the meantime, remain Secretary of Defense, the White House said Congress should waste no time in confirming his replacement.

“We have 66,000 men and women deployed in Afghanistan, and we need our new secretary of defense to be a part of significant decisions about how we bring that war to a responsible end," a White House press release reads.

Hagel’s confirmation will continue in the coming days after the Senate returns from a weeklong recess.

McCain told NBC's "Meet the Press" that he expects Hagel to be confirmed next week, despite calling him "the most unimpressive (nominee) that I've ever seen."

"No, I don't believe he's qualified, but I don't believe we should hold up his confirmation any further," he said. "I think it's a reasonable amount of time to have questions answered, not two days' worth."

Hagel has been under fire from both the left and right for, respectively, controversial remarks he made about gays and lesbians in the past and his sharp criticisms of former President George W. Bush's foreign policy.