Senate Republicans on Thursday, angered after Majority Leader Harry Reid Harry Mason ReidGraham signals support for confirming a Supreme Court nominee this year Trump signals he will move to replace Ginsburg 'without delay' Senate Republicans signal openness to working with Biden MORE (D-Nev.) blocked amendment votes on a bill, threatened to torpedo legislation they support on extending tax breaks.

If Republicans follow through, it would be the second time this week that a bipartisan bill was stopped in its tracks because of a broader fight over Senate floor procedure.

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Reid has refused to allow amendments on a bill that hit the chamber floor that would revive more than 50 tax breaks, commonly known as "extenders," that lapsed at the end of 2013.

Finance Committee Chairman Ron Wyden Ronald (Ron) Lee WydenGOP senator blocks Schumer resolution aimed at Biden probe as tensions run high Republican Senators raise concerns over Oracle-TikTok deal Hillicon Valley: TikTok, Oracle seek Trump's approval as clock winds down | Hackers arrested for allegedly defacing U.S. websites after death of Iranian general | 400K people register to vote on Snapchat MORE, who crafted the tax extenders plan with Sen. Orrin Hatch Orrin Grant HatchBottom line Bottom line Senate GOP divided over whether they'd fill Supreme Court vacancy MORE (R-Utah), offered to work with the GOP on amendments after the measure cleared another procedural hurdle on Thursday.

But Minority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellMomentum growing among Republicans for Supreme Court vote before Election Day Trump expects to nominate woman to replace Ginsburg next week Video of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral MORE (R-Ky.) wasn’t interested.

"The time to negotiate amendments is before cloture is invoked," McConnell said on the Senate floor. "But I appreciate that the Senate Finance Committee chairman is moving in the right direction.

“We want to have amendments before cloture is invoked,” the minority leader added.

Even Hatch told reporters on Thursday that he was leaning toward voting to block the bill on Thursday.

“It’s more important to assert our rights than to do anything else,” said Hatch, the top Republican on the Finance Committee. “I consider the way the Senate is being run right now to be an absolute tragedy. It’s inexcusable.”

Republicans had been pushing an amendment to repeal the medical device tax in the Affordable Care Act, an idea that has received broad bipartisan support in a nonbinding vote last year.

But now they are threatening to scuttle the tax bill amid a long-running fight with Reid over Senate operations.

Most Republicans also voted to block an energy efficiency measure earlier this week, after the bill from Sens. Jeanne Shaheen Cynthia (Jeanne) Jeanne ShaheenSenate Democrats introduce bill to sanction Russians over Taliban bounties Trump-backed candidate wins NH GOP Senate primary to take on Shaheen Democratic senator urges Trump to respond to Russian aggression MORE (D-N.H.) and Rob Portman Robert (Rob) Jones PortmanRomney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery House passes B bill to boost Postal Service MORE (R-Ohio) got caught up in the debate over the Keystone XL pipeline and the lack of amendment votes in the Senate.

Lawmakers and lobbyists had thought the extenders package might have a better shot of pushing through the Senate, because it contained pet provisions for many senators.

The $85 billion package would extend the popular research credit for business, a popular tax credit for the wind industry and tax breaks for teachers and commuters through 2015.

Along with those, other tax breaks derided by critics as corporate pork, including incentives for NASCAR track owners and Puerto Rican rum distillers, would be revived by the legislation.

“If our guys are getting shut out, I think it’s awfully hard to be for this process, even though most of us support the bill,” said Sen. John Thune John Randolph ThuneWhat Senate Republicans have said about election-year Supreme Court vacancies The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Trump contradicts CDC director on vaccine, masks MORE (S.D.), a member of both GOP leadership and the Finance panel.

The Republicans' threat comes as the party has intensified rhetoric against Reid, with Sen. Dan Coats Daniel (Dan) Ray CoatsFBI chief says Russia is trying to interfere in election to undermine Biden The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Trump, Biden renew push for Latino support Former Intel chief had 'deep suspicions' that Putin 'had something on Trump': book MORE (R-Ind.) saying the majority leader had a “dictatorial position.”

Reid has countered that it’s Republicans who are gumming up the works in the Senate.

“This useless, mind-boggling obstruction is what continually grinds the wheels of the Senate to a halt,” he said earlier this week during the energy efficiency debate.

Sen. Chuck Schumer Chuck SchumerVideo of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral Graham signals support for confirming a Supreme Court nominee this year Pelosi orders Capitol flags at half-staff to honor Ginsburg MORE (N.Y.), the No. 3 Democrat in the chamber, told reporters he was “befuddled” by the GOP opposition to a bill broadly supported by the business community – their own “bread and butter,” as Schumer put it.

“It’s a pro-business package. It’s a pro-people package, too,” Schumer said. “It’s hard to figure.”

Conservative groups like the Club for Growth and Heritage Action, though, have come out against the Senate plan, charging that many of the tax breaks benefit special interests.

Schumer added that Senate Democrats wouldn’t embrace the House GOP approach to the expired provisions – extending some permanently, while declining to restore others. “That’s not going to fly,” he said.

Even if Wyden and Republicans do negotiate over amendments, it is far from clear that Democrats would allow a vote on the medical device tax.

Wyden said on the Senate floor on Thursday that he would discuss amendments relevant to the tax extenders bill.

He blocked attempts to attach a medical device tax repeal when the Finance Committee considered the extenders package, arguing that it wasn’t among the tax provisions that have expired or are set to expire.

Wyden, who backed repeal of the tax last year, added this week that he planned to take a similar approach when the package was on the Senate floor.

Ramsey Cox contributed.

This story was last updated at 1:28 p.m.