The Senate has decided to create a buffer against the political consequences of deciding which of the nation's 3,600 military installations should be closed - a commission that can be conveniently blamed if the folks back home complain.

The Senate voted 83-13 on Tuesday to create a 15-member commission that would recommend which bases to close. The House is expected to agree to the commission, senators said during debate over the proposal that was tacked onto a Pentagon budget bill.Studies by the Pentagon and the Senate Armed Services Committee have estimated that between $1 billion and $5 billion a year can be saved if unneeded bases can be closed.

Sen. Strom Thurmond, R-S.C., summed up the political dilemma Tuesday when he told colleagues: "The real issue is one that concerns each of us - and that is the potential loss of jobs in our states and resulting economic dislocations. These are very real concerns."

Sen. John McCain, R-Ariz., said, "There is a perception in the country, and I think it's accurate, that Congress cannot act to close a single base because of the political ramifications."

The Pentagon has not closed any major U.S. installations since 1977, when Congress erected a series of stiff legal barriers to the periodic attempts to pare down the nation's military infrastructure.

The Pentagon last proposed closing bases in 1985, when it said 22 facilities could be shut down. But that idea ran into a storm of opposition on Capitol Hill and was later dropped.

As it works through the bill, the Senate is also trying to answer another politically tricky question of whether to have the military more deeply involved in the anti-drug fight.

Defense Secretary Frank C. Carlucci said Tuesday he opposes such moves. "I do not believe law enforcement, making arrests, is appropriate" for the military, he told a Senate subcommittee. "I think it is unwise to get the military into the law enforcement question. . . . Do we shoot people? Do we shoot down planes?"

The House voted 385-23 last week to order President Reagan to have the military seal U.S. borders against drug traffickers, and a similar plan is expected to be offered to the Senate.