President Trump’s deal for Russia to release diesel into global markets has angered his Republican allies, drawn a warning from European leaders and raised questions about whether it is even legal — all, Bloomberg reported, for a price cut that may never arrive before the Nov. 3 midterm elections.

The agreement, announced late last week, calls for President Vladimir V. Putin to begin releasing diesel supplies as part of a U.S. effort to bring prices down from record highs. Mr. Trump also intensified demands on President Volodymyr Zelensky of Ukraine to stop attacking Russian refineries and announced what he called an energy ceasefire between the two sides.

The wager is that cheaper fuel wins votes next month. On Sunday, a bipartisan group of senators argued that Mr. Trump should “reverse course” on the plan. “The United States should not provide Putin with a financial lifeline while Russia continues to kill Ukrainian civilians,” the senators said in a statement.

Europe reacted coldly as well. “We would call on the US to put the sanctions in place so that actually we could finish this war, so that all the effects of these attacks on refineries would not be there,” Kaja Kallas, the European Union’s top diplomat, told reporters in Luxembourg on Monday before a meeting of the bloc’s foreign ministers. Officials there warned the deal would bolster Moscow’s war effort; they want more sanctions instead.

Then there is the law. A 2022 statute prohibits the United States from buying most Russian energy products, and it is not clear how Mr. Trump plans to get around it. Senator Roger Wicker, a Mississippi Republican, is among the lawmakers who have said they do not expect the deal to go through.

The ceasefire itself may not exist. Mr. Trump acknowledged on Monday that neither side had actually committed to stop attacking the other’s energy infrastructure. “They agreed. You know why? Because I said you agree,” he told reporters. “That’s why they agreed — because I said they agreed.” He added: “I think actually Putin wants to make a deal more than Zelenskyy.”

Keith Kellogg, the president’s former envoy to Kyiv, dismissed the friction with Mr. Zelensky as “noise” and said he did not expect anything like the two men’s Oval Office argument of February 2025. “The rhetoric will kind of take care of itself,” Mr. Kellogg said. “Look at what’s happening on the ground.”

What is happening on the ground offers little relief. Diesel prices have stayed near record highs mostly because of the Iran war, which has throttled traffic through the Strait of Hormuz. Russia added to the shortage by extending a ban on diesel exports through September, after waves of Ukrainian drone strikes hit its refineries.

The first release, of 2.25 million barrels in October, is 1.4 million barrels less than American consumers used in a single day early this month. Shipments from Russia to the East Coast typically take more than two weeks, and record-high shipping costs would likely push prices higher anyway. American farmers and truckers, in other words, should not expect cheaper fuel before the election.

Russia, for its part, gave mixed signals on how much it can deliver. Alexander Novak, the deputy prime minister, said monthly diesel exports of 3 million tons — near the levels seen before Ukraine’s drone campaign — would be possible only after December. But in an appearance on the news program Vesti on Monday, Mr. Novak went further, as Al Jazeera reported: “By the end of the year, we could reach supply volumes of 3.5 million tonnes per month to global markets, just as was the case before the crisis.”

“There is no indication that any diesel is making its way to the US just yet,” Alex Kokcharov, a Bloomberg geoeconomics analyst, wrote in a note. “Given questions around the legality of easing sanctions and Russia’s own export capacity, it’s not clear this will result in any net increase to global diesel supplies.”

Whether any shipments restart in earnest depends on the ceasefire holding. Neither Russia nor Ukraine has said it agreed to one.