"We have been trying to confirm Mr. Southers since he cleared committee, including at the end of this session," Reid's spokesperson Jim Manley said in a statement to ABC News. "Sadly the Republican obstructionism of just one person, Sen. DeMint, prevented TSA from having the leadership in place that the organization deserves."
DeMint used the opportunity to argue against the unionization of TSA employees, saying that the agency is able to make quick decisions in the event of a terror incident because its employees are not unionized.
"Many Americans aren't aware that the president's nominee to lead the TSA appears ready to give union bosses the power to veto or delay future security improvements at our airports," DeMint said. "I hope this incident will lead the president to rethink this policy and put the interests of American travelers ahead of organized labor."
Experts say both Democrats and Republicans need to stop the political bickering on national security.
"I don't think it ought to be a political issue, and I didn't think it should be when I -- we were in office," Napolitano's predecessor, Michael Chertoff, told ABC News. "Unfortunately some people made it a political issue."
Former Bush administration national security official Gordon Johndroe said Republicans should "move on beyond the union issues" being used by DeMint to block an up-or-down vote on Southers.
"We've got to move on beyond the union issues; they will get worked out, it's an issue that the Department of Homeland Security has been working out since it was created six years ago," Johndroe said Tuesday on "Top Line," adding that he thinks DeMint's parliamentary maneuver is opening up Republicans a "little bit" to criticism from Democrats.
Experts are mixed on how the lack of a permanent director affects the agency. Some say that while terror plots such as the one last week are difficult to stop, having an agency head in place would make a difference.
"Any time you have an agency without political leadership, it drifts. New initiatives not put in play, reviews of old initiatives are not completed, it tends to drift," Peter Goelz, a former director of the National Transportation Safety Board and currently senior vice president at O'Neill and Associates, told ABC News.
But the TSA cannot entirely be blamed for Friday's incident.
"It is extraordinarily difficult to stop dedicated suicide bombers from carrying out their mission," Goelz said.
ABC News' Jason Ryan contributed to this report.