For Senator Amy Klobuchar, Democrat of Minnesota, there is always an egg-related angle.

After President Trump fired inspectors general last month, Ms. Klobuchar said that chaos and corruption were on the rise — along with egg prices.

When Mr. Trump’s numbers slipped in polling, she wrote on social media, “Verdict in the egg aisle: Yep! Trump’s honeymoon is over.”

And when she was booed at an event after mocking Mr. Trump onstage, Ms. Klobuchar offered a message to any Republican who, she suggested, might want to throw eggs at her in outrage.

“You can’t,” she cracked. “Because they’re too expensive.”

For years, Republicans hammered the Biden White House over inflation, riding a wave of frustration about the high cost of living back to total control of Washington.

Now, out of power and under pressure from their constituents, Democrats are struggling to press a unified and effective message against Mr. Trump. But some, like Ms. Klobuchar, are racing to turn the soaring costs of basic goods back on the administration.

They argue that while Mr. Trump won with promises to lower the cost of living, his White House is preoccupied with divisive policies and empowering billionaires rather than focusing on making life more affordable for most Americans.