The differences between former President Trump and Florida Gov. Ron DeSantis (R) are coming into sharper focus as the two emerge as potential rivals in the 2024 presidential contest. Trump’s endorsement helped propel DeSantis through a GOP primary in the 2018 Florida governor’s race. But as both men position themselves for a White House run, long-simmering differences on vaccines, pandemic responses and other issues are bubbling to the surface. Some of DeSantis’s policy positions are in direct conflict with Trump’s. That sets up a contrast for the Florida governor to highlight should he run against Trump for the 2024 GOP...