President Trump’s 2020 re-election bid starts Tuesday with a rally in Orlando, Fla., more than two years after making clear he would seek a second term.

Holding a launch rally after the campaign effectively gets under way is hardly a new political play; President Obama announced his 2012 re-election bid more than a year before his first official rally, and early Democratic 2020 front-runner Joe Bidenheld his “kickoff rally” about a month after he entered the race.

Still,...