Kansas Republican Sen. Roger Marshall argued on Wednesday that Ukraine’s war with Russia — rather than the U.S. conflict with Iran — is responsible for soaring diesel prices that threaten his party’s control of Congress in the upcoming midterms.

The response, delivered during a debate with Democratic challenger Adam Hamilton, aligned Marshall with President Donald Trump’s increasingly hostile stance toward Ukraine, which has spent more than four years defending itself against an invasion. Trump contends Ukrainian strikes on refineries in Moscow are driving up fuel costs and suggested importing Russian diesel to ease the issue.

Marshall hesitated at the idea on Wednesday, admitting “it doesn’t sound like a great idea.” However, he added, “if this brings Russia to the bargaining table, and it ends the war, then I am all for it right now.”

Hamilton strongly condemned Marshall’s position, stating that “nobody believes” Ukraine is responsible.

“What you said just now is you’re going to sell out our friends in Ukraine,” Hamilton said. “That’s not OK.”

The encounter was the second and final debate in the Kansas Senate race ahead of the Nov. 3 election. Marshall is seeking a second term in a tight contest, even though Kansas hasn’t elected a Democrat to the Senate since 1932. Hamilton serves as founder and senior pastor of the country’s largest United Methodist church.

Diesel costs are a major issue in Kansas because of its agricultural economy. On the campaign trail, Hamilton has repeatedly linked high fuel prices to an “unnecessary” war with Iran launched by Trump. AAA data shows diesel averaged $6.32 a gallon this week, compared to $3.62 a gallon a year ago.

Hamilton called for a temporary pause on federal fuel taxes while the war in Iran continues and vowed to push Trump to end that conflict. Marshall said he wants the war ended swiftly, without pledging to force that outcome.

Marshall also sought to link Hamilton to liberal Democrats’ Green New Deal policies aimed at moving the U.S. economy to renewable energy to fight climate change, arguing those proposals have blocked new diesel refineries from being built.

Hamilton noted that he backs elements of the Green New Deal, but not the full package.