WASHINGTON (AP) — Pressure is building on fractious House Republicans over legislation to prevent a partial government shutdown, as the Democratic-led Senate is expected to strip a tea party-backed plan to defund Obamacare from the bill.

As the Senate telegraphed its moves, House Republicans deliberated an array of imperfect options on both a temporary spending bill required to avert a shutdown and a separate measure to permit the government to borrow almost $1 trillion to keep paying its bills.

Lawmakers face a midnight Monday deadline to complete a stopgap spending bill to avoid a partial government shutdown that would keep hundreds of thousands of federal workers off the job, close national parks and generate damaging headlines for whichever side the public holds responsible.

The timeline is daunting since House GOP leaders appear all but certain to reject the Senate’s attempt at a simple, straightforward stopgap spending bill like those routinely passed since the 1995-96 government shutdowns that bruised Republicans and strengthened President Bill Clinton.

A 21-hour talkathon by Sen. Ted Cruz, R-Texas, whipped up the GOP’s tea party wing even as it complicated efforts by House GOP leaders to assemble rank-and-file support for a temporary spending measure.

Cruz wants to derail the spending bill to deny Democrats the ability to strip out the anti-Obamacare provision, a strategy that has put him at odds with other Republicans who say the move won’t work and fear it would spark a shutdown.

Many GOP senators, including the Senate’s top two Republicans, have said they’ll vote to advance the measure rather than filibuster it to death, a vote that promises to give Democrats controlling the chamber a procedural edge in a subsequent vote to kill the tea party’s effort to use the must-pass bill to derail Obamacare.

Wednesday evening, Senate Majority Leader Harry Reid, D-Nev., unveiled his version of the stopgap spending bill, which would keep the government running through Nov. 15. It also contains, for now, the anti-Obamacare provision sought by Republicans. He set in motion a key vote on Friday that promises to expose the divide between Cruz and more pragmatic Republicans. Senate passage of the spending bill — stripped of the Obamacare provision — was expected no later than Saturday.

“Any senator who votes with Majority Leader Harry Reid and the Democrats … has made the decision to allow Obamacare to be funded,” Cruz told reporters after his marathon speech ended Wednesday at noon. Cruz himself has predicted that is exactly what the Senate will do, and he’s already called on House Republicans to reject the bill when it comes back to them.

The simplest thing for Republicans to do would be to accept the Senate bill and send it to the White House for Obama’s signature, a prospect that’s unappealing to Republicans because it would make them look like they’re surrendering. House Speaker John Boehner, R-Ohio, originally preferred a plan to deliver to Obama a stopgap funding bill without the Obamacare provisions.

Now, GOP leaders are exploring adding face-saving options — like the repeal of a tax on medical devices, which many Democrats also oppose — to the stopgap spending bill. There’s also sentiment to take away the health insurance subsidy awarded lawmakers now that they’ll be required to purchase health care on Obamacare exchanges.

The House is expected to approve a measure this week allowing the Treasury to borrow freely for another year, although that legislation, too, would include a provision to carry out the Republican campaign against Obamacare. While no final decisions have been made, party officials said a one-year delay was likely to be added, rather than the full-fledged defunding that is part of the spending bill awaiting action in the Senate.

The GOP’s demands on the debt limit involves far less dramatic spending cuts than Republicans demanded from Obama in a debt showdown two years. Then, Republicans extracted $2.1 trillion in cuts over a decade for a similar increase in the borrowing cap. Now, GOP leaders are mulling a 14-month borrowing increase that would increase the debt ceiling by almost $1 trillion but are considering only modest cuts, like an increase in the contribution federal workers make to their pensions.

Shutdown-averting stopgap spending bills traditionally have been steered clear of these kinds of battles for fear of a politically damaging shutdown. But with the new health care law poised to enroll millions of people into Obamacare starting Oct. 1, there’s a new urgency among opponents to pull out all the stops to try to derail it.

Health and Human Secretary Kathleen Sebelius told reporters this week that consumers will have an average of 53 plans to choose from, and her department estimated the average monthly individual premium for a benchmark policy known as the “second-lowest cost silver plan” would range from a low of $192 in Minnesota to a high of $516 in Wyoming. Tax credits will bring down the cost for many.

Republicans counter that the legislation is causing employers to defer hiring new workers, lay off existing ones and reduce the hours of others to hold down costs as they try to ease the impact of the bill’s taxes and other requirements.

“Obamacare is destroying jobs,” Cruz said. “It is driving up health care costs. It is killing health benefits. It is shattering the economy.”