The House Ways and Means Committee opened formal hearings Wednesday on the sweeping artificial intelligence moratorium bill that cleared the Senate by a single-vote margin the previous evening, setting up a two-week deliberation that lobbyists, lawmakers and industry executives say will determine whether the most aggressive federal restraint on AI development in U.S. history reaches the president’s desk.

Chairman Rep. Marcus Halloran, R-Ohio, gaveled in the session shortly after 10 a.m. with a measured opening statement that left both sides guessing at his ultimate intent. Halloran described the Senate bill as “a serious response to a serious problem” but warned colleagues against “pricing American innovation out of a market that China is racing to capture.” He committed the committee to a full markup by April 21.

The legislation, co-authored by Sen. Bernie Sanders, I-Vt., and Rep. Alexandria Ocasio-Cortez, D-N.Y., would impose an 18-month pause on the training of frontier AI systems above a defined compute threshold, freeze new permits for hyperscale data centers in jurisdictions classified as water- or grid-stressed, and direct the Treasury to study a federal excise on training runs exceeding the cap. Tax provisions in the bill — the trigger that routed the legislation to Ways and Means rather than Energy and Commerce — include a proposed surcharge on cloud-compute revenues earned from frontier-model contracts.

Tuesday’s Senate vote, 52-48, was finalized just before 9 p.m. after a four-hour floor stretch. Three Republicans crossed over to join most Democrats and the chamber’s two independents, while five Democrats voted no, citing concerns about job creation in their states and competitiveness with Chinese model developers. Sanders, speaking outside the Senate chamber after the vote, called the result “a hinge moment” and said he was “more confident than I was a month ago that the House will follow.”

Inside the Ways and Means hearing room Wednesday, the early witness list pointed to the political stakes. The committee heard from the chief executives of two mid-tier cloud providers, the chair of the Federal Trade Commission’s AI task force, a Tennessee Valley Authority deputy administrator, and Dr. Priya Saraswat, director of the Brookings Center for Technology Policy, who testified that “an 18-month pause, properly scoped, is recoverable; an unmanaged buildout of compute on a grid that cannot supply it is not.”

Halloran pressed Saraswat on whether a shorter pause — six or nine months — could yield the same regulatory benefit. “It would not,” she replied. “The cycle time on frontier training runs is now under six months. A meaningful pause must outlast at least two cycles.”

Industry pushback was immediate and well-coordinated. By midmorning the Information Technology Industry Council had circulated a letter signed by 47 companies warning that the Senate bill, if enacted unaltered, would “redirect tens of billions of dollars in committed capital away from U.S. soil within a single fiscal year.” A separate coalition of small AI startups, organized under the banner Builders for Open Compute, sent its own letter — this one urging the committee to preserve the moratorium’s threshold-based design, which they argued would shield smaller developers from rules tailored to a handful of hyperscalers.

Lobbying inside the Capitol intensified throughout the day. Chief executives from at least three frontier AI firms were seen entering the Longworth and Rayburn buildings; one, accompanied by a senior policy lead, was overheard telling staff at the elevator bank that he had three more meetings before he flew back to the West Coast. A senior House Democratic aide, granted anonymity to discuss internal whip counts, said the bill’s supporters were “around three votes short” on the committee but had “real movement” on two members who had been previously listed as no’s.

Ocasio-Cortez, who does not sit on Ways and Means, spent much of the afternoon working the hallway outside the hearing room. Speaking with reporters, she rejected the industry’s competitiveness argument as “a phantom China that conveniently materializes whenever Washington tries to regulate anything.” She added: “We are not pausing research. We are pausing a build-out that the grid cannot carry, that communities did not consent to, and that has not produced the productivity gains its sponsors keep promising.”

President Donald Trump has not publicly committed to a position on the legislation. Press Secretary Karoline Renfro, asked Wednesday whether the president would sign the bill if it reached his desk in roughly its Senate form, said only that “the president is reviewing it carefully and will have more to say in the coming days.” Two White House officials, speaking on condition of anonymity, said internal opinion was split between economic advisers wary of the bill’s growth implications and a separate camp — including elements of the national security staff — who view a temporary slowdown as compatible with export-control objectives.

The committee’s calendar, as outlined by Halloran, schedules a second hearing for Thursday with witnesses from organized labor and a panel of state utility regulators, followed by industry-led testimony Friday. Markup is tentatively set for April 16 with a final committee vote no later than April 21. If the bill clears Ways and Means, it would go to the Rules Committee before reaching the floor.

Markets registered the day’s uncertainty. Shares in three of the largest publicly traded AI infrastructure firms declined between 1.4% and 2.6%, while a basket of regional utilities with heavy data-center exposure traded flat. Bond markets were largely unmoved.

Outside the Capitol, a coalition of climate, labor and consumer-advocacy groups rallied near the East Front, joined briefly by Sanders. Organizers said similar events were being planned in eleven state capitals in the days ahead. Sanders told the crowd that “the same Congress that bailed out Wall Street can find the courage to pause a build-out it cannot oversee,” and pledged to spend the next two weeks “in every member’s office that will have me.”

Committee staff said additional witness slots would be announced Thursday morning.