Top executives from the country’s largest cloud and chip companies blanketed Capitol Hill on Monday in a final push to peel off Senate Democrats from a sweeping moratorium on large-scale artificial intelligence model training, hours before a floor vote that industry lobbyists conceded was likely to pass.

The legislation, introduced March 26 by Sen. Bernie Sanders, I-Vt., and Rep. Alexandria Ocasio-Cortez, D-N.Y., would impose an 18-month freeze on the training of so-called frontier AI models above a defined compute threshold, citing strain on the electricity grid, unresolved labor displacement and a Government Accountability Office report on data-center water use. A companion House bill is expected to be taken up by the Ways and Means Committee later this month.

By midafternoon, lobbying disclosures filed with the Senate clerk’s office showed at least 41 separate meetings involving registered representatives of the four largest U.S. cloud providers, two leading semiconductor firms and the AI Forum, an industry trade group formed last year. Several chief executives appeared in person, ferried between offices in the Hart and Russell buildings by aides clutching binders of economic impact briefings.

“The pace today is unlike anything I’ve seen on a tech bill,” said Marcus Halloran, a former Commerce Committee staffer now with the consultancy Beacon Ridge Strategies. “They are leaving nothing on the table because the math is bad for them and they know it.”

Senate Majority Leader Chuck Schumer scheduled the vote for Tuesday afternoon over the objections of several committee chairs who had asked for additional markup time. Aides to Schumer said the Iran conflict and rising electricity prices had compressed the political window and that further delay would invite procedural mischief from both flanks of the caucus.

Whip counts circulated by both sides on Monday evening pointed to a narrow majority for the measure, with as many as three Republicans, both independents and a clear majority of Democrats supporting passage. At least five Democrats — including senators from states with significant data-center construction pipelines — were either opposed or uncommitted. Sen. Mark Warner, D-Va., whose state hosts the largest concentration of hyperscale data centers in the country, told reporters outside the chamber that he remained “deeply uncomfortable with a flat moratorium” but declined to say how he would vote.

Industry executives focused much of their pressure on those holdouts. Diane Karras, chief executive of the chip designer Tessera Logic, met Monday morning with senators from Virginia, Oregon and Arizona, according to two people familiar with her schedule. In a brief statement afterward, Karras said the bill as drafted “would idle billions of dollars in capital expenditure already committed to American facilities and effectively cede the next training generation to Chinese labs that face no such constraint.”

Supporters of the moratorium dismissed those warnings as overstated. In a news conference on the Senate steps, Sanders and Ocasio-Cortez argued that the 18-month pause is narrowly drawn, applying only to training runs above a defined floating-point operations threshold and exempting medical, scientific and open-source models that fall below it. “Nobody’s laptop is getting confiscated,” Ocasio-Cortez said. “What we’re saying is that before five companies double the electricity draw of the American Midwest, the public deserves a seat at the table.”

Sanders cited testimony last week from the Energy Information Administration projecting that frontier-model training and inference could account for as much as 9 percent of U.S. electricity demand by 2028 if current build-out plans proceed unchecked. He also pointed to layoffs at several customer-service and coding firms over the past quarter, which he attributed to generative AI deployment.

Polling released Monday by the Pew Research Center found 58 percent of Americans support a temporary pause on the largest AI systems, with majorities in both parties favoring some form of federal limits on data-center electricity use. Support softened, however, when respondents were told a pause could delay U.S. competitiveness against China.

That trade-off has animated the Trump administration’s posture, which has been notably ambivalent. White House Press Secretary Karoline Leavitt said Monday that the president “has concerns about heavy-handed regulation of an industry where America leads” but stopped short of issuing a veto threat. Two senior administration officials, speaking on condition of anonymity, said the president had been lobbied directly by at least three cloud-company chief executives over the weekend and remained “genuinely undecided” about how to position the bill if it reaches his desk.

Republican leadership has been similarly fractured. Sen. Josh Hawley, R-Mo., a longtime critic of large technology companies, is among the Republicans expected to support the moratorium. Senate Minority Leader John Thune and most of his leadership team oppose it, citing competitiveness concerns.

Wall Street took a measured view. Shares of major cloud providers were broadly flat in Monday trading, while shares of two large utility holding companies serving data-center corridors in Virginia and Texas closed up between 1.4 and 2.1 percent on speculation that a pause could relieve transmission bottlenecks.

“The market is pricing in a high probability of Senate passage but a coin flip in the House,” said Priya Venkatesan, an analyst with the brokerage Calderwood Securities. “Capital expenditure guidance from the hyperscalers next quarter is where this really starts to bite, not in today’s tape.”

A vote on the measure is expected after 3 p.m. Tuesday. The House Ways and Means Committee is scheduled to begin its own deliberations later this month, with hearings tentatively set to run into the third week of April. Industry officials said they were prepared to redirect their lobbying focus to the lower chamber within hours of any Senate outcome.