The Senate is expected to send the fiscal 2010 defense authorization bill to President Obama late Thursday, and he is likely to sign it despite objections to its funding for a controversial backup jet fighter engine.

The Senate voted 64-35 to limit debate on the final version of the legislation, which the House endorsed on Oct. 8. That paves the way for a vote by day’s end to send the bill to Obama.

The administration earlier threatened to veto the $680.2 billion defense policy measure if Congress persisted in promoting a second engine for the F-35 Joint Strike Fighter. But congressional Democrats consider that unlikely. now, and point out that Obama will still have a chance to block the second engine in the defense appropriations bill that is still making its way through Congress.

Congress has continued the engine program despite the objections of the Pentagon, providing a total of $560 million for the effort. Backers of the additional spending note that they are complying with the fiscal 2008 defense authorization law, which required the Defense secretary to ensure that sufficient annual amounts are obligated and expended, in each fiscal year, for the continued development and procurement of two options for the F-35 propulsion system. They suggest cutting funds would disrupt the program.

Senate Armed Services Committee Chairman Carl Levin , D-Mich., has said he does not expect the bill to be vetoed.

The final bill authorizes $130 billion for the wars in Iraq and Afghanistan during the fiscal year that began Oct. 1, and a 3.4 percent pay raise for troops. It also would ratify many Pentagon proposals to scale back major weapons programs that are popular in the districts of individual members.

Additionally, the bill would back Obama’s new plan for missile defense in Europe, which shifts from radar and missile sites in Poland and the Czech Republic to a ship- and land-based approach, using smaller and far less costly missiles. The provision would permit the administration to reallocate fiscal 2009 money that was once slated for missiles in Eastern Europe to implement the president’s plan.

The legislation also rewrites some of the Bush administration’s rules for interrogating and prosecuting wartime detainees.