Jeb Bush
The Jeb Bush–Trump dynamic was one of the more contentious relationships among the Republican contenders. Bush's campaign spent tens of millions of dollars on anti-Trump ads, while in response Trump mocked Jeb Bush with the epithet that he was "low energy". During an exchange with Jeb Bush in the ninth Republican primary debate, the audience (most favoring Bush) repeatedly booed Trump. Trump scoffed that the audience was made up of "Jeb's special interests and lobbyists".