House Democrats are threatening to vote against the first wave of fiscal 2019 spending bills, forcing Republicans into a familiar fight with themselves over government funding that could leave them headed for another government shutdown threat in September.

Minority Leader Nancy Pelosi, D-Calif., is urging Democrats to vote against an upcoming “mini-bus” package that pulls together a few spending bills into one bill.

Without Democratic support, the measure could falter thanks to the usual opposition from staunch fiscal conservatives.

The House plans to vote Friday on the first bill — the Energy and Water, Legislative Branch and Military Construction and Veterans Affairs Appropriations Act for fiscal year 2019. It’s the first in what House and Senate Republicans plan as a series of minibus measures that would allow Congress to avoid a yearslong habit of passing nearly all federal spending in one massive omnibus package.

Pelosi, however, told fellow Democrats to vote against the bill, even though the top-line funding for all 2019 nonmandatory spending will adhere to a bipartisan deal secured in March.

Pelosi’s opposition stems from provisions within each bill that many Democrats oppose, such as one permitting firearms on land controlled by the Army Corps of Engineers and language that would repeal an Obama-era water regulation and place new limitations on the Clean Water Act.

“The GOP mini-bus package on the Floor this week is partisan, wrong-headed and dangerous,” Pelosi wrote to fellow Democrats.

If Democrats uniformly oppose the measure, Republicans could have a hard time passing it on their own.

The House Freedom Caucus, made up of three dozen fiscal conservatives, isn’t sure it wants to support the bill yet, which boosts spending by billions of dollars above what President Trump requested and is part of an overall fiscal 2019 spending agreement that will increase the deficit.

Freedom Caucus Chairman Mark Meadows, R-N.C., said he fears the House is following a strategy that will hold the most difficult-to-pass bills for much later in the year, leaving little time for a resolution and requiring a last-minute omnibus once again.

“If you start off with the easy ones to pass we’re going to end up with an omnibus in September,” Meadows said. “For me, I want to see what the ultimate strategy is. We’re not taking an official position. I think we’ve got to get back together and talk to some of our folks.”

Republicans need many in the Freedom Caucus to help pass the minibus if Democrats oppose it.

Rep. Mike Simpson, R-Idaho, a key appropriator, said he believes the Freedom Caucus lawmakers will ultimately support the bill.

“In the end, I think they will,” Simpson said. “At least I hope.”

Pelosi is wishing for the opposite result, and she told Democratic colleagues that this outcome would empower the minority party in the spending negotiations that still lie head. Republicans would have to turn to them for support.

“House Democrats’ strong opposition to Republicans’ cynical strategy last year gave us powerful leverage in the omnibus,” Pelosi wrote to Democrats. “That leverage enabled us to fight off Republicans’ poison pill riders and secure dramatic increases in funding for key priorities, such as veterans, health and biomedical research, the opioid crisis, education and child care, and election security. That included nearly doubling funding for Child Care Development Block Grants, achieving a $3 billion increase for the National Institutes of Health, and providing $380 million in Election Security Grants.”

Freedom Caucus conservatives know they too have leverage and are withholding support, at least for now.

“I have not decided on that,” Rep. Jim Jordan, R-Ohio, a key Freedom Caucus member who is also running to succeed Speaker Paul Ryan, R-Wis., told the Washington Examiner.

If the minibus measures can’t pass Congress, Congress could be forced to consider another omnibus measure before the Sept. 30 end of the fiscal year.

Fights over the size and contents of past omnibus measures has provoked spending fights and constant threats of partial federal government closures. It’s a scenario the GOP majority has been striving to avoid on the orders of Trump, who warned Congress in March he won’t sign another massive omnibus.

Senate Majority Leader Mitch McConnell, R-Ky., is keeping the Senate in session through most of August in part to pass spending bills, he said Tuesday.

He was asked what would happen if the House can’t pass minibus measures and send them to the Senate, which is now an increasing possibility.

“I’m not going to answer every hypothetical,” McConnell responded.