They are competing for the nomination.
Trump continues to be respectful of Cruz, but is essentially saying I may at some time have to make the case for why I should be the nominee instead of Ted.
Nothing wrong with that.
Did you catch this part of Trump's quote?....
"I guess we’ll have to go to war,"
Does that sound like a respectful way to contrast their candidacy? Sounds more like more of the same tactics from Trump......Obnoxiousness and Insults.