"The acting TSA administrator is very able, and we have a solid team of professionals at TSA," Pfeiffer said.
"But Senator DeMint and others should put their short-term political interests aside and allow the Senate vote on the confirmation of the President's nominee to head the agency."
Obama nominated Southers on Sept. 11, nearly eight months after taking office, a delay that White House officials say was necessary to identify "the appropriate candidate" for the job.
In the wake of Friday's incident, Republicans have criticized the TSA and the Obama administration. But one of their own has single-handedly prevented new leadership at the agency. DeMint has refused to allow a vote on the nomination as long as Obama insists on permitting TSA workers to participate in collective bargaining negotiations, as other unionized government workers do.
In an interview on "Fox News Sunday," DeMint accused the administration of being intent on "unionizing and submitting our airport security to union bosses [and] collective bargaining."
Senate Majority Leader Harry M. Reid (D-Nev.) criticized Republicans on Tuesday, accusing them of "playing politics with national security" by stalling the nomination.
"Despite his qualifications and being reported out by two Senate committees earlier this year, Republicans have decided to play politics with this nomination by blocking final confirmation," Reid said in a statement.
"Not only is this a failed strategy, but a dangerous one as well with serious potential consequences for our country."