Senator Chuck Schumer of New York, the minority leader, is facing a torrent of criticism for choosing to vote with his Republican counterparts to head off a government shutdown.

Some of the sharpest barbs have come from another New York Democrat, Representative Alexandria Ocasio-Cortez.

Ms. Ocasio-Cortez blasted Mr. Schumer’s efforts to gather enough Democratic support so Republicans can clear a procedural hurdle and pass a measure to fund the government through Sept. 30, accusing him of ceding the sliver of power Democrats had over President Trump.

“I believe that’s a tremendous mistake,” she said in a CNN interview on Thursday.

And she had specific criticism of the legislation itself. “This turns the federal government into a slush fund for Donald Trump and Elon Musk,” she said. “It sacrifices congressional authority, and it is deeply partisan.”

Her sharp remarks even stirred talk about whether she would consider challenging Mr. Schumer, 74, in a primary when he is up for re-election in 2028. Asked directly in the television interview if she would consider such a campaign, she sidestepped the question but did not shoot down the premise.

The House Democratic leadership — with yet another New York legislator at the top — quickly followed Ms. Ocasio-Cortez’s criticism, putting out a statement knocking Mr. Schumer’s caucus for going along with Republicans. All but one House Democrat voted Tuesday against the plan, which would slightly decrease spending overall.