Senate Majority Leader Harry ReidHarry Mason ReidTrump thanks Reid for warning Democrats not to underestimate him Reid warns Democrats not to underestimate Trump Harry Reid predicts Trump, unlike Clinton, won't become more popular because of impeachment MORE (D-Nev.) threatened to pull a small-business bill off the Senate floor Thursday evening after a blowup with Sen. Olympia Snowe (R-Maine).

Snowe angered Reid when she attempted to secure a vote on an amendment that would restrict the federal government’s ability to impose regulations by mandating economic studies on the impact of those regulations.

Snowe tried to add the Small Business Regulatory Freedom Act to the list of the amendments the Senate will consider in relation to small-business legislation.

Reid said the maneuver threatened to bring down the entire bill, which has been stuck on the Senate floor since March 14.

Tempers flared as Reid and Snowe argued back and forth over the amendment.

“My friend from Maine’s legislation is not relevant or germane to this legislation,” said Reid, who was visibly irritated. “What is going to happen if she objects to the consent which I have offered, this bill will not go forward, and that is too bad."

Reid said he was “terribly disappointed” that Snowe “is going to cause this legislation to fail,” something he said was all the more galling because as the ranking member of the Senate Small Business Committee, Snowe should recognize the importance of the underlying small-business legislation.

A senior Democratic aide called it “one of the most important pieces of legislation of this Congress."

Reid is growing frustrated with how long the bill has spent on the Senate floor and the snarl of procedural objections that have stalled it.

"I'm disappointed that my friend from Maine's killing this legislation," Reid said. "That's what it amounts to. We've spent enough time on this legislation."

Snowe bristled at the notion that her amendment is not relevant.

“If you would ask the small-business community exactly what is their major priority in the United States Congress, it would be regulatory reform,” Snowe said. “Undeniably, it is one of the most onerous burdens placed on small businesses today and our economic well-being."

Snowe’s amendment, which she introduced with leading conservative Sen. Tom CoburnThomas (Tom) Allen CoburnThe Hill's Morning Report — Presented by PhRMA — Worries grow about political violence as midterms approach President Trump’s war on federal waste American patients face too many hurdles in regard to health-care access MORE (R-Okla.), would require federal agencies to carefully consider the impact of proposed regulations on small businesses.

It would require analyses of the economic impact on small businesses; set up judicial review of proposed regulations to give small businesses greater power to challenge regulations; and require all federal agencies to have panels to review potential impacts on small businesses.

But Reid found Snowe’s argument unconvincing, to put it mildly.

“The more she talks, the more reason there is not to do this amendment,” Reid said.

Reid argued that Democrats are just as interested in sparing small businesses from onerous regulation: “And for her to suggest that regulation reform is something that she’s all-knowing about ... I understand regulation reform."

The Senate adjourned at 7:55 pm without resolving the dispute. Lawmakers will have a chance to resolve it when they return to Washington on May 2 after a two-week recess.