Young voters, according to an analysis of exit polls, also helped Jacky Rosen, a Democrat, win the Senate seat in Nevada, and contributed to Beto O’Rouke’s strong showing against Ted Cruz in the Texas Senate race. In Florida, the Harvard research showed, young voters chose the Democratic candidate for governor, Andrew Gillum, over Mr. DeSantis, 62 percent to 36 percent, though Mr. Gillum ultimately lost.
John Della Volpe, director of polling at the Institute of Politics, said that politics had become more tangible for younger adults in recent years.
The attitudes of youth started to shift after the 2016 election, from fear to hope for the future, he said. Then came Parkland on Feb. 14. A “traumatized generation” became an “energized generation,” which Mr. Volpe expected would help shape a more progressive domestic agenda and demand gun control legislation.
“Parkland turbocharged a movement that was going to happen anyway; the tragedy gave them some momentum,” he said. The Parkland students helped the movement, he added, by giving “youth very specific ways to engage: register to vote, sign a petition, call a lawmaker.”
At least one person associated with Parkland saw the Florida midterms as a victory.
Hunter Pollack, 21, is the brother of Meadow Pollack, 18, who died in the shooting. Mr. Pollack’s father appeared in a political ad for Mr. DeSantis.
“The F.B.I. failed my sister. The Broward Sheriff failed my sister. The Broward School Board failed my sister, and Andrew Gillum was a candidate who aligned himself with those failed politicians,” Hunter Pollack said.