A veto of the fiscal 2017 defense policy bill is a "foregone conclusion" thanks to the election and the resulting lame-duck government, according to experts.

Andrew Hunter, a defense analyst at the Center for Strategic and International Studies, said Tuesday that vetoing the defense bill would not have much impact on President Obama's legacy, and that Sen. John McCain, who heads up the Senate Armed Services Committee, could be a lame-duck chairman if he either loses his seat or Republicans lose control of Congress.

That dynamic is setting up a situation in which at least one veto of the National Defense Authorization Act is likely, he said.

"I can't think of another year where the veto was a foregone conclusion," he said on a panel at a Heritage Foundation event.

Last year, Obama vetoed the fiscal 2016 defense policy bill over funding concerns, but eventually signed a final bill before the end of the year.

Congress will return to Washington next week to a full plate of defense matters it should settle before the end of the fiscal year on Sept. 30.

While Justin Johnson, an analyst with the Heritage Foundation, said it's possible lawmakers could get the authorization bill done before the end of September, the appropriations bill, which failed to pass the Senate twice before August recess, is stuck without an obvious way to pass it.

"I would place a priority for each of these bills on getting it done right, not getting it done by Sept. 30," Johnson said.

Some of the sticking points lawmakers must reconcile between the House and Senate version of the policy bill include whether women must sign up for the draft and specifics on Pentagon acquisition reform. The Senate version, for example, gets rid of the top acquisition, technology and logistics post while the House bill does not.

The Senate bill also proposes some radical changes to Goldwater-Nichols, which governs organization of the military. Katherine Kidder, a fellow at the Center for a New American Security, said that even if the substance of those reforms is good, getting so much done so quickly could be difficult.

"I think it's instructive to remember that when original Goldwater-Nichols reform was laid out, it took four years of legislative process to build it," she said.

The biggest difference is in funding. The House moves $18 billion from the war chest toward base priorities, which will leave troops overseas out of money by March unless lawmakers in the new Congress pass a supplemental funding bill. The Senate bill, on the other hand, matches the administration's requested amount.

Ultimately, due to a tight timeline in an election year and impasses in the Senate on the spending bill, most experts predict that the Pentagon will begin the fiscal year on a continuing resolution, as it has in many recent years.

"I would expect at least the initial CR to go into December. There's the potential for a second going beyond that, but the most likely scenario is around December, Christmas time for better or for worse," Johnson said.