President Trump is struggling to land a punch on the governor of Florida, Ron DeSantis, who’s positioning for an expected run at the Republican presidential nomination with stealth jabs at Mr. Trump’s weaknesses, such as making bold declarations that the Sunshine State is a lock for the GOP in 2024.

On the Brian Kilmeade Show, Mr. DeSantis demonstrated that he won’t fight Mr. Trump insult-for-insult, but on more favorable terrain of his choosing. “It’s the silly season,” he said of Mr. Trump’s slights. Imagine the former president’s outrage at being so dismissed, since “silly” is the exact kind of branding at which he has excelled.

Facing an unconventional opponent, Mr. DeSantis is taking conventional steps like publishing a campaign biography, “The Courage to Be Free: Florida’s Blueprint for America’s Revival.” The book tour has provided him the opportunity to cast his record in contrast to Mr. Trump’s diminishing support in the party and the nation.

“Americans love a winner,” General George S. Patton said, “and will not tolerate a loser.” Mr. DeSantis can tout himself as a proven winner, in stark contrast to Mr. Trump, who won the Electoral College in 2016 but lost the popular vote and went on to lose both in 2020, although he spun his vote total as historic for an incumbent.

“We were able to go from winning by 32,000 votes to winning by over 1.5 million votes,” Mr. DeSantis said in an interview on Fox News Channel, “sweeping Hispanics by over 60 percent, winning Miami-Dade County by double digits.” Note the use of “winning” twice and exaggerating his margin with Hispanics into a sweep.

“We have built in an infrastructure for Republicans to where Florida should no longer be considered a swing state,” Mr. DeSantis said. “This is a state that we have this strong advantage in now.” This may seem a routine boast, but it strikes at Mr. Trump’s Achilles heel.

Greek legend tells that Achilles’s mother, Thetis, dipped her infant son in the river Styx, conferring invulnerability on his entire body except for the heel where she held him to perform the baptism. In 2016, Republican rivals and the Democratic nominee, State Secretary Clinton, went at Mr. Trump’s armored spots — a mistake Mr. DeSantis has yet to repeat.

The quality of “electability” matters a lot to pundits and party voters. While it didn’t bring success in the general election for Mrs. Clinton or the 2004 Democratic nominee, John Kerry, it did help them dispatch primary challengers who voters felt would go on to lose in November.

GOP voters are tired of silver medals. The party has won the popular vote just once since 1988, and running a base-only election — as Mr. Trump did in 2020 — is a sure way to fall short again. In 2016, Mr. Trump tapped into this yearning for success. “We’re going to win so much,” he often told supporters, “you may even get tired of winning.”

At one event, Mr. Trump invoked “winning” 15 times in about half a minute, once every 2.4 seconds. Republicans cheered when he was delivering for their agenda, but he lost in 2020, and his insistence that the election was stolen have worn thin, like fans of the Buffalo Sabers who still complain that a bad overtime goal cost them the 1999 Stanley Cup.

Putting Florida out of Democratic reach is an accomplishment Mr. Trump cannot hope to match, and Mr. DeSantis doesn’t need to add asterisks to his losses because he doesn’t have any. He beat the Democratic candidate for governor by 20 percent, six times Mr. Trump’s two victories.

In addition, Mr. DeSantis is pointing to besting Democrats on their home turf, like Miami-Dade, laying the groundwork to claim he can flip Georgia and other states that Mr. Trump lost by narrow margins to Mr. Biden.

Without the Sunshine State, the nation’s third-largest, the electoral map is stacked against the GOP. Look for Mr. DeSantis to use its new status as solidly Republican to chip away at Mr. Trump’s mantle of “winner” and brand the former president with his favorite insult of all: Loser.