One thing was clear when former President Donald J. Trump decided to skip the first debate of the 2024 Republican primary race: There would be a vacuum to fill.
But it was not Mr. Trump’s chief rival in the polls, Gov. Ron DeSantis of Florida, who emerged at the epicenter of the first Trump-free showdown on Wednesday, but instead the political newcomer Vivek Ramaswamy, whose unlikely rise has revealed the remarkable degree to which the…