Senate Democrats on Wednesday joined with Republicans to approve an annual defense bill, defying a veto threat from President Obama.

The Senate voted 70-27 in favor of the $612 billion National Defense Authorization Act (NDAA), a wide-ranging measure that would set policy and spending priorities for the Pentagon. Twenty Democrats voted yes, as did Sen. Angus KingAngus Stanley KingDrama hits Senate Intel panel’s Russia inquiry Warner, Burr split on committee findings on collusion Overnight Defense: Top general wasn't consulted on Syria withdrawal | Senate passes bill breaking with Trump on Syria | What to watch for in State of the Union | US, South Korea reach deal on troop costs MORE (Maine), an Independent who caucuses with Democrats.

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While the vote total would be enough for Republicans to override Obama’s promised veto, Democratic leaders insist that some of their members would vote differently if asked to override the president.

“The president is going to veto this. Everyone knows this,” Senate Minority Leader Harry ReidHarry Mason ReidConstitutional conservatives need to oppose the national emergency Klobuchar: 'I don't remember' conversation with Reid over alleged staff mistreatment Dems wary of killing off filibuster MORE (D-Nev.) said ahead of the vote. “The House, if they are called upon first to sustain the veto, they will do it. If we’re called up on first to sustain the veto, we will do it.”

Republican Sens. Ted CruzRafael (Ted) Edward CruzPoll shows competitive matchup if O’Rourke ran for Senate again Democrats veer left as Trump cements hold on Republicans O’Rourke heading to Wisconsin amid 2020 speculation MORE (Texas) and Rand PaulRandal (Rand) Howard PaulBusiness, conservative groups slam Trump’s national emergency declaration The Hill's 12:30 Report — Presented by Kidney Care Partners — Trump escalates border fight with emergency declaration On The Money: Trump declares emergency at border | Braces for legal fight | Move divides GOP | Trump signs border deal to avoid shutdown | Winners, losers from spending fight | US, China trade talks to resume next week MORE (Ky.), who are both running for president, were the only Republicans to vote against the bill. Two other 2016 candidates, Sens. Lindsey GrahamLindsey Olin GrahamThe Memo: Trump and McCabe go to war Graham seeks new Rosenstein testimony after explosive McCabe interview Senate confirms Trump pick William Barr as new attorney general MORE (S.C.) and Marco RubioMarco Antonio RubioOn The Money: Trump declares emergency at border | Braces for legal fight | Move divides GOP | Trump signs border deal to avoid shutdown | Winners, losers from spending fight | US, China trade talks to resume next week Trump declares national emergency at border Democrats veer left as Trump cements hold on Republicans MORE (Fla.), didn't vote.

The policy bill has been pulled into the larger battle over the GOP’s budget plan, which would appropriate $38 billion to the Pentagon through a war fund account.

Democrats and the White House say the war fund should not be used to skirt congressional budget caps and are demanding that Republicans negotiate a deal to raise spending across the federal government.

But Republicans, and even some Democrats, have questioned why Obama is poised to veto the NDAA, as the bill authorizes spending without actually appropriating the money.

"You know, I started to have conversation with the White House when we were taking this up in committee, telling them their veto threat was a mistake," said Sen. Tim KaineTimothy (Tim) Michael KaineOvernight Defense: Trump declares border emergency | .6B in military construction funds to be used for wall | Trump believes Obama would have started war with North Korea | Pentagon delivers aid for Venezuelan migrants Kaine asks Shanahan if military families would be hurt by moving .6B for border wall Clinton on GOP promoting Trump 'stronger together' quote: Now copy my policies too MORE (D-Va.), who voted in favor of the NDAA on Wednesday.

"To basically say you'll veto over the [war fund] issue, when we have language in the bill that basically says we should fix the budget caps, I said, 'I think you're drawing the line in the battle at the wrong place.' "

The policy bill has passed Congress for 53 consecutive years, and is typically considered one of the most important legislative tasks for Congress.

Sen. John McCainJohn Sidney McCainMark Kelly's campaign raises over M in days after launching Senate bid The Hill's 12:30 Report — Presented by Kidney Care Partners — Lawmakers wait for Trump's next move on border deal Mark Kelly launches Senate bid in Arizona MORE (R-Ariz.), the chairman of the Senate Armed Services Committee, said an Obama veto of the defense bill would be “shameful.”

“If the president vetoes the NDAA, at this time of mounting global threats, he will be prioritizing politics and process over the security of our nation and the well-being of our armed forces.”

Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGreen New Deal Resolution invites big picture governing ‘Contingency’ spending in 3B budget deal comes under fire Coulter defends Paul Ryan: This is 100 percent Trump's fault MORE (R-Ky.) echoed that criticism Wednesday.

“If he does [veto the bill], it will be the latest sorry chapter in a failed foreign policy based on campaign promises rather than policies to realistically meet the threats before us,” he said.

Obama has threatened to veto the policy bill six times before, primarily due to objections on the transfer of prisoners from the Guantánamo Bay prison facility, but never followed through.

But this year will be different, the administration says, due to the president's strong objections to the use of the war fund.

Press secretary Josh Earnest this week called the GOP plan an “irresponsible way to fund our national defense priorities” and reiterated that Obama would reject it.

Rep. Mac Thornberry (R-Texas), the chairman of the House Armed Services Committee, suggested that if Obama vetoes the bill, it would be different from the four times the NDAA has been vetoed in the past 53 years.

"Every one of them were because of something that was in the bill, not because of something that was outside bill, which is thing the president is complaining about today," he said.

If and when Obama’s veto comes, Republicans are likely to try for an override, though success appears unlikely. The House fell short of the two-thirds majority needed to override a veto when it voted on the NDAA last week. And Sen. Dick DurbinRichard (Dick) Joseph DurbinTrump praises law enforcement response to shooting at Illinois business Five dead in shooting at manufacturing plant in Aurora, Illinois ‘Contingency’ spending in 3B budget deal comes under fire MORE (D-Ill.) warned on Tuesday that Republicans should not assume that Senate Democrats voting for the NDAA would also vote to overturn Obama’s veto.

"If we can't override [a veto] ... outside events will dictate the future and the fate of the legislation," McCain said. "We need 67 in the Senate. It will be very interesting to see how many we hold."

Some military groups have warned Obama against holding the policy bill hostage to the larger funding fight. 

The Military Officers Association of America (MOAA) and the Reserve Officers Association have both sent letters to the president urging him to support the NDAA.

MOAA President Norbert Ryan Jr. said while the concerns about the extra war funding are “legitimate,” the policy legislation “is vital to fulfilling wartime requirements.”

— This story was updated at 5:19 p.m.