WASHINGTON — Defying a White House veto threat, the Senate voted decisively Tuesday to approve a defense policy bill that authorizes $602 billion in military spending, bars shuttering the prison at Guantanamo Bay, and denies the Pentagon’s bid to start a new round of military base closings.

The GOP-led Senate’s version of the National Defense Authorization Act passed 85 to 13, with all but seven members of the Democratic caucus backing the legislation. Six Republicans voted against it.

The legislation mandates for the first time in history that young women sign up for a potential military draft. The requirement has angered social conservatives, who fear the move is another step toward the blurring of gender lines akin to allowing transgender people to use public lavatories and locker rooms.

The Republican-led House passed its version of the defense bill last month and lawmakers from both chambers must meet in a conference to resolve differences. The House, for example, excludes the female draft requirement and seeks $18 billion more in spending than the Senate to pay for troops and weapons the Pentagon didn’t request.

The defense bills authorize military spending for the fiscal year that begins Oct. 1.

But there is agreement in both chambers on key policy provisions — such as keeping Guantanamo open — that puts Congress on a collision course with President Obama.

The House and Senate also have agreed not to allow military bases to be closed.

Military bases are prized assets in local economies and shutting them can cost votes in the next election. Besides, several lawmakers have argued that the Pentagon has cooked the books to justify its conclusions or at least didn’t do the math completely.

Associated Press