Sen. Bob Corker, R-Tenn., ranking member of the Foreign Relations Committee, visited Afghanistan and Pakistan last weekend to assess plans to wrap up the military engagement.
NATO announced in June national security forces in Afghanistan have the lead in securing the country as the 2014 transition deadline approaches. British officials said Afghan troops may have a tough road ahead as militant activity kicks into high gear during the summer months.
Corker said Afghan national security is a lingering near-term challenge. The next few months, however, may turn out to be a test of the country's long-term stability.
"I hope that President Obama will make his decision on the remaining troop presence after 2014 in a timely fashion based on our national security interests, including the continuing need for robust counter-terrorism operations," he said in a statement Monday.
The White House plans to cut the U.S. troop presence but not eliminate the military obligation completely. NATO said its mission would transition to an advisory role in 2014.
CBS News said Tuesday the White House is mulling a complete withdrawal, however, because of tensions over bilateral affairs with Afghan President Hamid Karzai.
Karzai said he was frustrated with diplomatic outreach efforts involving the Taliban.