That’s Mostly False.

In checking previous instances when DeSantis made this same claim, PolitiFact found no evidence that critical race theory, a broad set of ideas about racism being woven into American systems, was being taught in Florida’s K-12 schools in the first place. Educators, school officials and several Florida public school districts told us that CRT has never been part of the state curriculum.

PolitiFact found a few examples of state education officials objecting to textbooks and courses they said contained CRT teaching in recent years. They show the state’s objections to prospective teaching materials, and success in preventing content it deemed to be CRT-related. But questions remain about its rationale and broad definition of the theory and other prohibited topics.
-Aaron Sharockman, PolitiFact

Asked about how he would fix America's education system, DeSantis said "we need education, not indoctrination."

The governor defended keeping schools open during the COVID-19 pandemic and argued that the lockdowns were connected to students falling behind.

He also touted his response to the culture wars, saying Florida "eliminated" critical race theory and gender ideology in K-12 schools.

-ABC News' Hannah Demissie and Will McDuffie

On education, Ramaswamy says he would eliminate the Department of Education and make families more central to their children's educational choice. Central to Ramaswamy's campaign is that several federal agencies should be eliminated, but the idea of parental choice in education has swept through conservative states this year. Four Republican-led states passed new universal voucher programs that would allow parents to take tax dollars and spend them on private schools, including religious schools, or homeschool their children. More states have pushed for parental bills of rights that allow students' parents to have more of a say, and object to more, curricula.
-Analysis by Monica Potts of FiveThirtyEight

According to a Ipsos/Reuters poll from July, 77 percent of Republicans say that transgender athletes should not be able to participate in children’s sports at the elementary/high school level. Just 18 percent say they should, and 6 percent are not sure.
-Analysis by FiveThirtyEight

Recent election cycles have shown how debates can substantially alter a candidate’s trajectory. The debates won’t always do this, of course, and early primary polls remain relatively predictive of who will end up winning a party’s nomination. However, a candidate can earn a real polling bounce from a debate — or fall into a valley.

Primary polls are inherently more volatile than general election polls. In a general election, most voters already lean toward one party, so only a small part of the electorate is likely to shift its views over the course of a campaign. But in a primary, voters in one party may be open to multiple candidates because most contenders will share similar views on a number of issues. As a result, exposure to an unfamiliar candidate could prompt voters to begin considering that contender, while a strong or weak performance by a candidate they do know could make them look elsewhere.

For example, early in the 2012 cycle, Texas Gov. Rick Perry appeared to be now-Sen. Mitt Romney’s most serious opponent for the Republican nomination. But in a September 2011 debate, Perry defended a Texas policy that gave undocumented immigrants access to in-state college tuition. The backlash from the GOP base came swiftly, as Perry fell out of contention in the polls, well before a later debate in which he — oops — forgot the name of the third of three federal agencies that he aimed to dismantle as president. Four years later, former tech executive Carly Fiorina had very little support early in the 2016 Republican race, but in August 2015 she stood out in an “undercard” debate. Her polling numbers improved and she made the main stage in subsequent debates, giving her a platform that eventually led Texas Sen. Ted Cruz to make her his vice presidential pick in a last-ditch attempt to rally support against Trump in the 2016 primary.

-Analysis by Geoffrey Skelley of FiveThirtyEight