WASHINGTON — When the Senate approved legislation last week for $700 billion in defense spending in 2018, lawmakers once more left out a provision sought by the Pentagon – a plan to save $10 billion by consolidating and shutting down a number of military bases in the next five years.

It was 12th time the Pentagon has sought to trim the number of bases. But members of Congress with targeted bases in their districts fear shutdowns could hurt their local economies, although military officials say such effects would be temporary.

Members of Congress are “looking out for short-term political interests and the local economy in their districts,” said Dan Grazier, a former Marine Corps captain who is now a fellow at the Center for Defense Information, a think tank of former military officials that analyzes Pentagon policy and spending.

In a recent report, the Pentagon concluded that it had 22 percent more infrastructure than it needs. It wants Congress to create a Base Closure and Realignment Commission that would recommend which bases to trim, while still retaining some excess capacity. Consolidations or closures could be done without reducing the military’s readiness or effectiveness, according to the report.

Critics of BRAC sometimes cite the high cost of closing military bases as a flaw in Pentagon planning. However, Defense Secretary James Mattis told a congressional committee that the Defense Department has proposed initiatives that would provide Congress with information it needs to make a cost-based decision.

Grazier agreed that the high cost of base closings could be “mitigated with discipline and restraining the budget.” He argued that a restrained budget not only forces the military to think better and make smart choices in terms of weapons and equipment that are easy to maintain on the field but also control the cost of base closures.

Sen. Jack Reed, D-R.I., opposed the last BRAC round in 2005 because it closed two bases in Rhode Island, Harwood U.S. Army Reserve Center Providence and USARC Bristol. Now he is working with Sen. John McCain, R-Ariz., to push legislation to authorize a new BRAC round for the fiscal 2018.

John Conger, a former Defense Department official who is now a senior adviser at the Johns Hopkins University Center for Strategic and International Studies, said he thinks there is a chance that a base closing plan could be enacted even though Congress rejected it last week. McCain’s support of a BRAC round is a “path on the road forward” despite the “long process of persuading” that lies ahead, he said.