TSA was created after 9/11 as part of the Department of Homeland Security. It has faced criticism from both Democrats and Republicans alike, most recently after a TSA screening manual for employees was posted online.
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.
"I think that it is a mistake that Kip Hawley hasn't been replaced. He was a pretty smart guy," said Peter Goelz, a former director of the National Transportation Safety Board and currently senior vice president at O'Neill and Associates. "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."
But the TSA cannot entirely be blamed for the incident on Friday, when 23-year-old Umar Farouk Abdulmutallab boarded a Detroit-bound plane strapped with explosives and tried to blow up the jetliner as it was about to land.
"It is extraordinarily difficult to stop dedicated suicide bombers from carrying out their mission," Goelz said.
Experts say men such as Abdulmutallab, who live seemingly normal lives, are hard to identify and target.
"This is the truly disturbing part," ABC News consultant and former counterterrorism official Richard Clarke said on "Good Morning America" Monday. "They are normal one day and then after a few weeks of watching the Internet and watching al Qaeda videotapes on the Internet, they become radicalized. They reach out in the real world for al Qaeda connections. They get trained.
"It's very hard to see these self-initiating terrorists become terrorists, very hard for U.S. intelligence to pick them up," Clarke added.
Terror plots and attacks against the United States in the past have tended to unite the two parties, but last Friday's foiled plan has done the opposite.
In addition to blaming DeMint for delaying Southers' nomination, some Democrats have singled out Republicans for voting against a funding measure in the 2010 appropriations bill for the Department of Homeland Security, which would provide additional funds to TSA for security systems.
Under the measure, the TSA would get more than $4 million for screening operations, of which $1.1 million would be for explosives detection systems, $855,964,000 for aviation security direction and enforcement and $778,300,000 for the purchase and installation of these systems. The measure also included $1.2 million for developing and enhancing research and training capabilities for TSA "improvised explosive recognition training."
House Minority Leader John Boehner, R-Ohio, was among those who voted against the measure. When reached for comment, his office would only say in a statement, "Boehner voted against the House Democratic Leadership's irresponsible efforts to import terrorists into the United States from the prison at Guantanamo Bay. Frankly, the attack on Christmas Day is another reminder that we need a real plan to protect America from the terrorist threat. Transparently partisan attempts to shift blame don't make the American people any safer."