President Donald Trump will meet with titans of the oil industry Friday who are battling among themselves over whether he should slap tariffs on Saudi crude to get the kingdom to reduce its output. It’s an idea championed by Oklahoma oil man Harold Hamm, a Trump confidant on energy who will be part of the meeting Friday, as well as some Republican senators who say tariffs could help the president win concessions from Saudi Arabia and stabilize the global crude market.

Tariffs are also a weapon of choice for the president, who has wielded it against China, foreign steel producers and during trade negotiations with Mexico and Canada. Within the oil industry, the idea has exposed deep rifts, with refiners firmly opposed.

“If they were to go down this route it would probably result in some refineries shutting down completely,” said Chet Thompson, head of the industry’s top trade group, the American Fuel & Petrochemical Manufacturers.

Trump has indicated he already has a plan in mind for helping oil companies he says are being “ravaged” by a price war between Russia and Saudi Arabia. He said he knows what to do to solve the problem, though he declined to reveal the strategy other than to say it’s “tough” and “I’d rather not do that.” Instead, the president said, he hoped Russians and the Saudis would strike an agreement to cut production.