President Trump is picking a fight with Senate Republicans right before the midterm elections with his surprise deal to allow Russia to export diesel to the United States.

Four Republican senators — Sens. Susan Collins (Maine), Lisa Murkowski (Alaska), John Curtis (Utah) and Thom Tillis (N.C.) — have already spoken out against the controversial deal between Trump and Russian President Vladimir Putin.

Many others are likely privately critical of the stunning move, which Trump executed without advanced warning or consultation with Republican senators.

“I think there are a lot more people that are privately critical of it. The question is whether they want to go public with it,” said Vin Weber, a GOP strategist and former member of the House Republican leadership.

The Senate just two months ago passed a tough Russia sanctions package, which Trump had delayed for months despite mounting pressure from fellow Republicans to embrace it.

“The bigger political risk for the president on this — if it’s a political risk — is there is a substantial base of support in his party for taking a very tough attitude on Russia which he does not seem to share,” said Weber.

As the days pass, more Republican senators are expected to condemn Trump’s deal with Russia, which will generate hundreds of millions of dollars for the Russian economy and could put it in a better position to continue the war against Ukraine. Under the deal, the U.S. would buy an estimated 2.5 million tons of fuel from Russia.

“The deep-seated support for Ukraine in this fight should not be underestimated [among] the Republicans or [among] America most broadly. Most Americans have spent their entire lives understanding that Russia is our rival at best and our flat-out enemy at worst,” Weber said. “They are deeply invested in supporting Ukraine emotionally and otherwise.”Trump is facing pressure to do something about high fuel and diesel costs that have been driven up by the war in Iran.

One senior Senate Republican aide expressed hope that the deal could give crucial help to Republican candidates in the final sprint to Election Day.

“Trump realizes that diesel prices are very high, and I think he’s trying to do anything he can do get it down. He did a deal with the devil from the looks of it,” the source said.

Danielle Pletka, a distinguished senior fellow specializing in U.S. foreign and defense policy at the American Enterprise Institute, called the diesel deal “a lifeline for Putin” at a moment when the Russian offensive has stalled out in Ukraine.

But she suggested that Trump is “desperate” to bring down diesel prices as polls now show Democrats favored to win the House and possibly the Senate, too, in next month’s election.

“It’s just an act of desperation by a president who doesn’t see the optics,” she said, calling the lifting of sanctions “a lifeline for Putin at a moment he’s losing ground. Looks like a pact between two desperate men.”Senators who voted for a tough new sanctions package against Russia aren’t happy about the prospect of the United States now buying hundreds of thousands of tons of Russian diesel, particularly when they’d worked for months to stop China and India from buying Russian energy products.

Collins, who is in a tough reelection fight in a state Trump has lost in his three presidential runs, criticized the commander in chief for not adhering to the Russia sanctions legislation he signed into law last month.

“I oppose President Trump’s decision to lift sanctions on the purchase of diesel from Russia. I was a cosponsor of the Russian sanctions law, which the President recently signed but is now not following,” Collins, who chairs the Senate Appropriations Committee, wrote on social media Sunday.

She joined three other Senate Republicans and three Democrats in a joint statement blasting Trump for flouting a 2022 statute banning Russian energy imports.

“Congress explicitly banned Russian energy imports in 2022 to prevent American dollars from financing Putin’s brutal war against Ukraine. Congress was clear: the U.S. should not import oil from Russia until it ends its aggression against Ukraine and ceases threats against our NATO allies,” Collins declared in a joint statement with fellow Republicans Murkowski, Tillis and Curtis, as well as Democratic Sens. Ron Wyden (Ore.), Richard Blumenthal (Conn.) and Jeanne Shaheen (N.H.), who is also the ranking member on the Senate Foreign Relations Committee.

“President Trump’s decision to allow Russian diesel imports to the U.S. runs directly counter to that law,” the senators declared, noting that the administration had failed to consult with Congress or offer an explanation to justify the lifting of sanctions on Russian oil as required by law.

Republicans acknowledge high diesel costs have become a major political headwind for GOP candidates in battleground races across the country.

Senate Majority Whip John Barrasso (R-Wyo.) said Trump is wrestling with a tough issue.

“The president is balancing and has to make tough decisions. He’s balancing his effort to stop and end … Putin’s war in Ukraine and lowering prices for American families,” he said Sunday on CBS News’s “Face the Nation.”Barrasso, one of Trump’s staunchest allies in the Senate, didn’t say whether he supported the deal with Putin and quickly pivoted to blaming Democrats for constraining domestic oil production.

He argued that the Russia sanctions bill that Congress passed earlier this year was intended to give Trump “flexibility and the firepower to use another tool against Vladimir Putin,” suggesting Congress gave the president full discretion over how to apply sanctions.

The senior Senate Republican aide noted that diesel prices have already fallen to $6.27 a gallon from the high of $6.53 a gallon in September.

“He’s just trying something to get the price down immediately as quick as he can. I’ve seen prices come down too at the pump,” the source said. “Whatever is happening, whether it’s something that Trump is doing or it’s happening naturally, it couldn’t come at a better time for him.

“If you look at all the battleground states, the price of diesel, the price of gas are going to be the two big drivers of how people in the middle are going to vote,” the aide added. “It will be huge for farmers around the country who are harvesting right now.”But Alex Jacquez, senior vice president for policy, advocacy and research at the Washington-based economic policy think tank Groundwork Collaborative, said the price of diesel is likely to stay above $6 through Election Day.

Jacquez estimated the deal would generate approximately $400 million for the Russian economy.

“It’s certainly not insignificant,” he said, but added “it’s not going to be the make-or-break” development in Russia’s war effort, either.

The impact on the U.S. economy is also likely to be modest. Jacquez predicted a “minimal” impact on domestic diesel prices.

“While 300,000 metric tons — 2.2 billion barrels — sounds like it’s a lot of barrels, which is why Trump is announcing it as such, that’s like half a day of diesel demand in the United States,” he said.

Jacquez previously served as a special assistant to former President Biden for industrial policy and economy development at the National Economic Council.