A Florida congressman asks if Mar-a-Lago can be taxed at the value Trump claimed it was worth.

Attempting to call former President Donald J. Trump’s bluff, a congressman from Florida on Thursday asked Palm Beach County to tax Mar-a-Lago, Mr. Trump’s seaside residence and private club, at the value he claimed it was worth, more than $1 billion.

The gambit, by Representative Jared Moskowitz, Democrat of Florida, goes to the core of New York’s civil case against Mr. Trump. The state has accused the former president of grossly inflating the value of his properties to obtain favorable bank loans while paying taxes on valuations at or below market value. Judge Arthur Engoron valued Mar-a-Lago at $18 million, the low end of the $18 million to $28 million appraisal used by Palm Beach County for property taxes.

Eric Trump, Mr. Trump’s son, speculated on X, the social media platform formerly known as Twitter, that the home and resort could be worth $1 billion. He called it “arguably the most valuable residential property in the country,” and said the judge’s figure was “an attempt to destroy my father and kick him out of New York.”

In a letter to the Palm Beach County Property Appraiser, Mr. Moskowitz asked, “If the property value of Mar-a-Lago is so much higher than it was appraised, will you be amending the property value in line with the Trump family’s belief that the property is worth well over a billion dollars?”