The Trump administration in its 2018 Defense Department budget proposal on Tuesday called for a new round of base realignment and closures, echoing a request that the Obama administration and senior military officers have made for years despite lawmakers repeatedly blocking it.

Initiating a new round of base realignment and closure, often known as BRAC, could save the military $2 billion per year, the administration said in budget documents as it pitched the idea anew. If it’s launched in 2018, BRAC could occur in 2021, the administration said.

Andrew Roth, the Pentagon’s acting comptroller, said in a news conference Tuesday that the Pentagon collectively saves about $12 billion per year as a result of previous rounds of BRAC, which were carried out in 1988, 1991, 1993, 1995 and 2005. The Defense Department now has about 20 percent more facilities than it needs, and the money needed to keep them open could be spent on military readiness, Roth said.

But base realignment has long been easier to propose than to execute. Lawmakers who have opposed additional rounds of BRAC have typically cited the negative economic impact it has on surrounding towns and cities as well as the upfront cost that goes with moving and building facilities that are needed.

The 2005 round closed 24 bases, reorganized about a dozen others and cut thousands of civilian jobs. But a Government Accountability Office investigation found that it cost $35.1 billion to complete, about 67 percent more than the $21 billion initially estimated. That cut the amount the Pentagon will save over the first 20 years to about $10 billion.

The GAO also has questioned whether it is accurate for the Defense Department to say it has 20 percent too many facilities, saying the figure was not derived from the same “data-intensive process” as earlier rounds of BRAC.

Roth said Tuesday that the Pentagon has received “some signals from at least a couple committees” in Congress that lawmakers have a more open mind about BRAC.

“We’ll be pushing that pretty hard,” he said.

Roth did not cite any specific examples of why the Pentagon thinks proposing BRAC now may receive a better reception on Capitol Hill, but a few key lawmakers have signaled their openness to it.

In January, Sen. John McCain (R-Ariz.), chairman of the Senate Armed Services Committee, criticized congressional “cowardice” on BRAC  and indicated that he and Sen. Jack Reed (R.I.), the committee’s ranking Democrat, were open to talking to Defense Secretary Jim Mattis about it.

Rep. Adam Smith (Wash), the ranking Democrat on the House Armed Services Committee, also reintroduced legislation in January aimed at allowing the Pentagon to carry out more BRAC. It makes no sense for the Defense Department to be required to keep open bases it does not need at taxpayer expense, he argued.

A Defense Department analysis of its infrastructure that was delivered to Congress last spring found that the Army has 33 percent “excess capacity,” the Air Force has 32 percent, the Navy and Marine Corps have 7 percent combined and the Defense Logistics Agency has 12 percent.

Critics, including Rep. Mac Thornberry (R-Tex.), chairman of the House Armed Services Committee, criticized the infrastructure report for basing its math on the smaller size of the military that the Obama administration approved.

“No one believes that the current military force structure is adequate to meet the threats we face,” Thornberry said at the time. “Just this month, senior commanders testified that our military is too small. Assessing our capacity based on an inadequate force structure makes no sense. It would lock in a future where our stressed military becomes permanently gutted.”