So-called progressive Democrats who suggested in a letter Monday that President Biden seek a diplomatic solution to the war in Ukraine “withdrew” that letter Tuesday after coming under blistering attack by more hawkish members of their own party.

Less than 24 hours after the letter landed on Mr. Biden’s desk, one of the letter’s signatories, Representative Pramila Jayapal, said it was drafted “several months ago” and was released by her staff without being vetted.

“Our message is being conflated by some as being equivalent to the recent statement by Republican Leader McCarthy threatening an end to aid to Ukraine if Republicans take over,” Ms. Jayapal, chairwoman of the House Progressive Caucus, said. “The proximity of these statements created the unfortunate appearance that Democrats, who have strongly and unanimously supported and voted for every package of military, strategic, and economic assistance to the Ukrainian people, are somehow aligned with Republicans who seek to pull the plug on American support for President Zelensky and the Ukrainian forces.”

“Nothing could be further from the truth,” she added.

The letter, signed by 30 Democratic members of Congress, urged Mr. Biden to pair America’s military and economic support for Ukraine with an approach more focused on diplomacy that includes negotiating with President Putin on a potential ceasefire in the interest of averting a nuclear war.

“As legislators responsible for the expenditure of tens of billions of U.S. taxpayer dollars in military assistance in the conflict, we believe such involvement in this war also creates a responsibility for the United States to seriously consider all possible avenues, including direct engagement with Russia,” the letter stated.

In suggesting that America consider its own interests and economics along with those of Ukraine on the path forward, the left-wing corners of the Democratic Party have aligned themselves with the right-wing fringe of the Republican Party that is also pushing for a more Trumpy “America first” approach to the war.

Last week, the man pegged to be the next House speaker if Republicans regain control of the body next month, Representative Kevin McCarthy, suggested that the flow of money to Ukraine from Washington might slow if and when he and his fellow Republicans take over.

“I think people are gonna be sitting in a recession and they’re not going to write a blank check to Ukraine,” Mr. McCarthy told Punchbowl News. “They just won’t do it. … It’s not a free blank check.”   

Since the Russian invasion, Congress has authorized tens of billions of dollars in emergency aid for Ukraine and Mr. Biden has shipped billions’ more worth of materiel via the Pentagon. The assistance had broad bipartisan support in the early going, but cracks have appeared more recently as more and more members of Congress — most of them Republicans — call for more oversight of how the money is spent.

The letter by the progressive caucus marks the first time that members of Mr. Biden’s own party have shown skepticism about the current policy. Its tone, in parts, parrots the concerns of Republicans in Congress about the economic toll the war is taking on the rest of the world.

“The conflict has also contributed to elevated gas and food prices at home, fueling inflation and high oil prices for Americans in recent months,” the letter states. “Economists believe that if the situation in Ukraine is stabilized, some of the speculative concerns driving higher fuel costs will subside and likely lead to a drop in world oil prices.”

While the White House said only, via spokesman John Kirby, that it appreciates the liberals’ “very thoughtful concerns,” more hawkish members of the party immediately pushed back. Senator Murphy of Connecticut cited the “moral and strategic peril” of sitting down with the Russians.

“Sometimes, a bully must be shown the limits of his power before diplomacy can work,” Mr. Murphy said on Twitter.

Another prominent liberal, Markos Moulitsas, the Daily Kos founder, was not so politic in his criticism of the progressives’ policy suggestions.

“These 30 House progressives are now making common cause with Lauren Boebert, Marjorie Taylor Green, JD Vance, and the rest of the MAGA crowd,” Mr. Moulitsas said. “Which Ukrainians do these ‘progressives’ want abandoned to mass murder and rape, in their attempt to prop up a flailing Russia? The only way to end this war is to help deliver a decisive Ukrainians victory.”