The campaign against the most contentious ballot question in Florida this year — an abortion-rights measure known as Amendment 4 — was relatively quiet until recently. But on its side all along was the most powerful figure in Florida politics: Gov. Ron DeSantis, who has gone all in on leveraging his considerable executive power to try to defeat the proposal.

Mr. DeSantis signed a ban last year on most abortions after six weeks of pregnancy, revving the Amendment 4 campaign into overdrive and putting fellow Republicans in the difficult position of having to defend an unpopular ban or defy the popular governor.

Last month, he gave shout-outs to Florida Republicans who had opposed the abortion amendment or contributed to the campaign against it, putting those who had not on the spot.

“Every one of our elected representatives needs to say where they stand on this,” he said at a state party dinner. “Some are not saying anything or offering to help us defeat this.”

The governor’s offensive might work. Under Florida law, ballot questions must receive 60 percent support to pass, a higher threshold than abortion-rights ballot measures have had to meet in other states.

Most public opinion polls show support for Amendment 4 barely reaching the threshold or just under it, though a recent poll by The New York Times and Siena College found support among likely voters much lower, at 46 percent.

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