Manchin and Sinema are coy about reviving parts of the Build Back Better plan. Democrats hope they're not being strung along.

• Democrats are hoping they can avoid having their economic agenda whacked under a "Goodfellas" scenario.
• Some Democrats believe a deal must materialize within two months or the party will fail.

Call it the Joe Pesci "Goodfellas" scenario for Democrats.

Like Pesci's character Tommy DeVito in the classic mob movie, their legislative agenda seems like it will be "made" into something close to untouchable. But at the last moment, two hitmen execute DeVito — who suddenly realizes he was strung along— and the stalled climate and social bill could face a similar fate at the hands of a pair of centrist holdouts.

After last year's total collapse in negotiations, Democrats are now preparing to take a final shot at approving a slimmer climate and healthcare spending bill. "The fact that we haven't been able to come up with something that we can agree on yet — it's just shocking to me," Sen. Tim Kaine of Virginia told Insider. "I think we need to get a deal."

They face a tricky situation balancing competing demands from Sens. Kyrsten Sinema of Arizona and Joe Manchin of West Virginia. They can't afford to lose either vote in the 50-50 Senate since they must all coalesce behind a bill to pass it over fierce GOP opposition. Manchin sank the House-approved package late last year and Sinema never publicly committed to it.

Kaine said he believes an agreement will be harder to clinch after Memorial Day. Democrats face a tough political landscape and the attention in Congress will soon turn to campaigning with the midterms in November inching closer. "My gut just tells me we're going to do this by Memorial Day or not," he said.

Taxes are an especially difficult sticking point with the two centrists holding often opposing views. Sinema has been steadfast in her opposition to increase tax rates on wealthy Americans and large companies. But rolling back the 2017 GOP tax cuts and stepping up taxes on the richest people has been a key Manchin priority. It's unclear if Democrats will ultimately be able to bridge those differences and clinch a deal.

In addition to raising taxes on the wealthy, Manchin wants to empower the federal government to negotiate prescription drug prices, secure new spending on an "all of the above" energy policy that includes fossil fuels, and cut the deficit.

"We'll just see if there's a pathway forward," Manchin told reporters on Tuesday about the prospect of new negotiations. "We don't know if there's a pathway forward yet."

Asked by Insider why should Democrats trust him to strike a deal when he hasn't committed to anything, Manchin shut down further questions. "I'm not talking anymore," he said.

Manchin threw cold water on additional federal spending on Tuesday after a new federal report showed prices rising at their fastest clip in four decades.

Politico reported that talks are still largely informal between the White House and Manchin. The Biden administration hasn't laid out any goals and Congressional Democrats are also trying to play it safe.

"Senator Manchin has always been a straight shooter with me," Sen. Ron Wyden of Oregon said in a recent interview. He's among the Democrats in the upper chamber trying to revive the spending bill.

But other hurdles may arise. Manchin has started voicing fresh skepticism about a key White House aim requiring most vehicles sold by 2030 to be powered by electricity. He's arguing a swift transition may be unattainable due to Chinese dominance of the materials needed for battery production.

Sinema, for her part, has cracked the door open to voting for a slimmer bill without laying out specifics. She vowed on Tuesday that she'd remain "the same person" in any future negotiations and not switch up her demands. The Arizona Democrat also wants to ensure additional federal spending is limited.

"I work everyday to ensure any government spending is targeted and thoughtful because a lean, efficient government helps avoid price hikes," she said last week in prepared remarks at a National Federation of Independent Business tax summit.

She added she's "always willing" to engage in negotiations but wants to ensure any spending package is "responsibly offset and that new revenue provisions protect qualified small business income where possible."

Republicans are hoping these Democratic efforts at a comeback fall apart. Senate Minority Leader Mitch McConnell said on Tuesday that he hopes Sinema's resistance to tax increases will be enough to "keep this thing underwater permanently."

Democrats are trying to salvage what's left of their legislative ambitions after last year's debacle ended in failure. Whether they avoid the elimination of their agenda under the "Goodfellas scenario" is up in the air for now.