After providing nearly $26 billion in aid to farmers over the past few years to offset losses from President Trump’s trade war with China, the administration now has another giant new pot of money to pass out to them with little or no oversight, courtesy of the $2 trillion coronavirus stimulus package.

The legislation, given final passage by the House on Friday and quickly signed into law by Mr. Trump, allocates as much as $23.5 billion in assistance for farmers and gives broad leeway to Agriculture Secretary Sonny Perdue to direct it where he sees fit.

The money was inserted into the bill by senators from farm states after an intense lobbying push by major corporate farming groups. Parts of the industry are suffering immediate hits from the coronavirus outbreak, such as corn growers who have seen prices for ethanol plummet and mom-and-pop suppliers of farm markets that have closed in many cities.

But unlike industries such as airlines, hotels and automakers, which have largely or completely shut down, most farms are still operating. And sales of some products in the industry have surged as worried consumers stock up, generating shortages of meat, chicken, eggs and flour.

The law provides Mr. Perdue with $9.5 billion to support farmers, including livestock producers, suppliers of farm markets and producers of specialty crops, and $14 billion in borrowing authority to replenish the fund he used to make trade-related payments to farmers in the past two years. The department’s entire discretionary budget request for next year is about $23 billion.

The Agriculture Department will also receive an additional $25.1 billion for food aid programs for poor families from the stimulus bill.

“We are effectively subsiding every other sector of the economy” in the $2 trillion stimulus package, said Joshua Sewell, a farming industry analyst at Taxpayers for Common Sense, which advocates less government spending. “So I guess the argument goes that agriculture wants its piece of the pie, too.”

The administration’s use of the money will become a major political factor in rural America in the middle of an election year in which Midwestern states could be pivotal, said Lawrence R. Jacobs, the director of the Center for the Study of Politics and Governance at University of Minnesota. He predicted that Mr. Trump would soon be trumpeting it as part of his re-election campaign.

“This is just an extraordinary and unprecedented opportunity in the modern era for a president to dole out cash,” he said. “In urban areas, they call this walking around money, which a politician hands out to secure support.”

A small army of groups mounted the fast-moving campaign for aid, including the politically powerful American Farm Bureau Federation and the National Cattlemen’s Beef Association. Joining them were other smaller players representing producers of goods like turkey, pork and potatoes or sunflowers, sorghum, peanuts and eggs.

Among their targets were farm-state lawmakers like Senators John Hoeven of North Dakota, who pressed for $50 billion in aid for agriculture. Others included Senators Pat Roberts of Kansas, John Thune of South Dakota and Mitch McConnell of Kentucky, the majority leader. All are Republicans who serve on the Senate agriculture committee or the appropriations subcommittee that oversees farm aid.

Senator Debbie Stabenow of Michigan, the ranking Democrat on the agriculture committee, was also lobbied.

“We want to make sure that farmers, ranchers and rural Americans are also recognized as needing assistance,” said Dale Moore, the executive vice president of the American Farm Bureau and a former chief of staff at the Agriculture Department.