WASHINGTON >> Republican senators blocked a bill today to keep the government operating and allow federal borrowing, but Democrats aiming to avert a shutdown are likely to try again — at the same time pressing ahead on President Joe Biden’s big plans to reshape government.

The efforts are not necessarily linked, but the fiscal yearend deadline to fund the government past Thursday is bumping up against the Democrats’ desire to make progress on Biden’s expansive $3.5 trillion federal overhaul.

It’s all making for a tumultuous moment for Biden and his party, with consequences certain to shape his presidency and the lawmakers’ own political futures.

Success would mean a landmark accomplishment, if Democrats can helm Biden’s big bill to passage. Failure — or a highly unlikely government shutdown and debt crisis — could derail careers.

“You know me, I’m a born optimist,” Biden told reporters today, as he rolled up his sleeve for a COVID-19 booster shot. “We’re gonna get it done.”

In today’s vote, senators voted 50-48 against taking up the bill, well short of the 60 “yes” votes needed to proceed. Democratic Majority Leader Chuck Schumer switched his “yes” to “no” at the end in order to allow Democrats to reconsider the bill later.

With days to go, Democrats are likely to try again before Thursday’s deadline to pass a bill funding government operations past the Sept. 30 fiscal yearend, stripping out the debate over the debt limit for another day, closer to a separate October deadline.

Meanwhile, the real action is unfolding behind the scenes over the $3.5 trillion measure, with Biden and his Democratic allies in Congress seeking a once-in-a-generation reworking of the nation’s balance sheets.

From fee pre-kindergarten and child care subsidies for families with small children to dental care and hearing aids for seniors with Medicare, there’s a lot in the president’s proposal — all to be paid for with higher taxes on corporations and the wealthy.

With Republicans solidly opposed, Democrats are rushing to trim the total and win holdouts within their own party.

Building on a separate $1 trillion bipartisan public works package that’s already cleared the Senate and is heading for a House vote, Biden is seeking major spending for health care, education and efforts to tackle climate change. The total price tag, he contends, is actually “zero” — covered by the expected increase in tax revenue.

He is personally calling fellow Democrats in Congress an effort to resolve differences and bring his sweeping domestic policy vision forward.

Ticking off the weighty list of goals to accomplish, Biden said: “If we do that, the country’s going to be in great shape.”

But Republicans say it’s real spending that can’t be afforded, and a reflection of the Democrats’ drive to insert government into people’s lives.

And so far, the bill is also too big for key Democrats whose votes are needed in the face of the GOP opposition. Two Democratic holdouts, Sens. Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, have said they won’t support a bill of that size. Manchin has previously proposed spending of $1 trillion to $1.5 trillion.

With all Republicans opposed, Democratic leaders can’t spare a single vote in the 50-50 Senate, relying on Vice President Kamala Harris to break a tie to pass the eventual package.

All this, as other deadlines swirl this week to pay for government operations and allow more borrowing or risk a devastating federal shutdown or debt default — though those dire scenarios appear unlikely.

The bill Senate Republicans rejected today would have funded government operations temporarily, to early December, while also providing emergency funds for Hurricane Ida and other disaster relief and for Afghan refugees in the aftermath of the 20-year war.

Republican leader Mitch McConnell rejected that approach because Democrats also included a provision to suspend the debt limit, which would allow continued borrowing to pay off the nation’s bills.

Once a routine matter, raising the debt limit is now a political weapon of choice wielded by Republicans to attack Democrats — even though both parties have been responsible for piling on debt.

“The Democrats will do the responsible thing—the right thing, the thing that has been done for decades by both parties—and vote yes,” said Majority Leader Schumer ahead of the vote

Schumer called the Republican opposition “unhinged.”

McConnell has said he wants to fund the government and prevent a devastating debt default, but wants to force Democrats to split the package in two and take the politically uncomfortable debt ceiling vote on their own.

“Republicans are not rooting for a shutdown or a debt limit breach,” he said.

Thursday is a new deadline of sorts, and Biden, House Speaker Nancy Pelosi and Schumer won some breathing room after Pelosi postponed today’s planned vote on the public works bill to Thursday, which is also the expiration date of transportation programs in the public works bill.

As Pelosi huddled privately today with House Democrats, the more difficult action now lies in the Senate, as Democrats are under pressure to amass the votes for Biden’s package.

Pelosi said Sunday it seems “self-evident” that the price tag will come down to meet the concerns of remaining lawmakers.

Her comments reflected the enormous stakes for the coming week, one that could define the Biden presidency and shape the political contours of next year’s midterm elections.

Democrats have only a few votes to spare in the House for Biden’s massive agenda. Some Republican senators did back the $1 trillion public works bill, but now House Republicans are objecting, saying it is too much.

While progressives say they have already compromised enough on Biden’s big bill, having come down from a bill they originally envisioned at $6 trillion, some are also acknowledging the more potential changes.

Biden’s proposal is to be paid for by increasing the corporate tax rate, from 21% to 26.5% on businesses earning more than $5 million a year, and raising the top rate on individuals from 37% to 39.6% for those earning more than $400,000 a year, or $450,000 for couples.

While Democrats are largely in agreement on Biden’s vision — many ran their campaigns on the longstanding party priorities — stubborn disputes remain. Among them are splits over which initiatives should be reshaped, including how to push toward cleaner energy or to lower prescription drug costs.