It’s called a Campaign, they are nasty things. Nothing new under the sun.
Yup, politics is a dirty, nasty game. If you’re not up to the fight, better not jump in.
Trump knows it’s early, he’s laying the groundwork. He has plenty of time to deal with the issues at his rallies coming up.
I don’t blame him for firing back, even at Republican challengers, at this stage of the game. He fights.