WASHINGTON — As U.S. lawmakers return to the brink of a government shutdown this week, defense insiders are hopeful Congress will find a path to a budget deal that eases military spending limits.

To get beyond the Dec. 22 deadline, lawmakers are mulling a third stop-gap spending bill that fully funds the Pentagon for 2018 but punts on other agencies until Jan. 19. It’s a rough match to the budget cap-busting, House-passed defense appropriations bill, with added missile defense funds requested by the Trump administration.

A large enough bloc of assertive House Republican defense hawks and fiscally conservative Freedom Caucus members are backing this so-called cromnibus that House Speaker Paul Ryan, R-Wis., has allowed it to advance.

But the proposal is likely dead in the Senate, where any legislation to ease caps needs a supermajority — which means at least eight Democrats must join Republicans.

Senate Minority Leader Chuck Schumer, D-N.Y., has insisted on parity for defense and nondefense, and his conference is rejecting the cromnibus. Democrats have mockingly dubbed the same measure the “Puntagon,” for kicking the can on nondefense spending.

“At this late hour it’s ... an unfortunate waste of precious time,” Schumer said Thursday. “House Republicans should have known not to waste everyone’s time with a partisan spending bill that could never pass the Senate.”

Early this week, the main event will be the Republicans sprinting to pass their tax overhaul. They hope to pass the bill in both chambers by the middle of this week, but as of couple days ago, GOP leaders say they have ironed out internal divisions and have the votes to pass it.

From there, time will be short to pass a government spending bill before the Dec. 22 deadline or shut down the government.

Because a Christmastime government shutdown could trip the GOP’s possible victory lap on the tax bill and stain the party heading into 2018 midterm elections, Republican leaders are motivated to make a deal.

“I can’t assure you that there won’t be a shutdown, but I can assure you that there’s a lot of members in the majority party running Congress, and a lot of the minority don’t want a shutdown and are thinking about how to avoid one,” said William “Doc” Syers, the Aerospace Industries Association’s vice president for legislative affairs.

With the midterm election year approaching and Republicans collaborating to reconcile divisions on tax reform, Syers was hopeful that “maybe a little of that spills over on working together to avoid a shutdown.”

The congressional ‘kabuki dance‘

As congressional leaders formulate the stop-gap continuing resolution, they’ll also be focused on the ultimate top lines for the defense and nondefense sides of the budgets.

There was an initial Republican offer several weeks ago to raise defense by $54 billion and nondefense by $37 billion in both fiscal 2018 and 2019 — for a total increase in base discretionary spending of $182 billion.

That would boost the defense limit to $603 billion from the fiscal 2018 cap of $549 billion; and increase nondefense to $553 billion from the cap of $516 billion.

Democrats responded with a counteroffer to increase both defense and nondefense by $54 billion, raising the two-year cost above $200 billion, Roll Call is reporting.

Jim Moran, a former Democratic congressman from Virginia who served for many years on the House Appropriations Committee, told Defense News he expects Democrats to ultimately accept the Republican proposal, or something close to it — after a CR is passed this week.

“There’s not going to be a shutdown, and the members will kick the can far enough down the road that they can all be home for Christmas with only a tinge of anxiety about what will happen when they get back,” said Moran, now a senior legislative adviser with McDermott Will and Emery.

Senate Democrats are privately saying that $37 billion is an acceptable increase, Moran asserted. Plus, any deal can be sweetened with issues important to members on both sides — the reauthorization of child health insurance, funding for a program that permits many veterans to receive private-sector medical care, and disaster relief for California, Texas and Florida.

“The Democrats are looking to next November [elections],” Moran said. “If the Democrats get too insistent about a no-compromise strategy, some of the blame [for a shutdown] might shift to them. Nobody’s interest is served by a shutdown.”

Moran predicted the House may send the partisan cromnibus to the Senate — “one more step in this kabuki dance” on the bill — and that it would be rejected in the Senate.

Lawmakers, he said, will be keen to reach a deal to fund the government and leave Washington to spend the Christmas recess with their families.

“Their wives are going to be furious if they’re not home by the evening of the 22nd,” Moran said. “They’ve all promised their wives — or whoever it is who pulls their strings — that they will be back by the evening of the 22nd.”