GOP Rep. Adam Kinzinger (Ill.) tore into former President Donald Trump Monday night, after the ex-president took offense to former President George W. Bush's criticism of domestic terrorism during a 9/11 commeration speech over the weekend.

"I mean, [Trump] proved George W.'s point as quickly and as amazingly as you can," Kinzinger told CNN's John Berman. "To anybody that's still kind of looking at Donald Trump as a standard bearer for the Republican party, this is one of the weakest men that I've ever seen."

On Monday, Trump issued a statement firing back at Bush for likening violent extremism and domestic terrorism to that which originates abroad, while suggesting both to be significant threats to the United States in their own ways. Although Bush did not specify who or what exactly he was referring to, there was speculation he was alluding to the Jan. 6 Capitol riot, and thus possibly a subsection of Trump supporters.

And Kinzinger, for his part, did not take Trump's possible defense of Capitol rioters or extremists well. "Somebody with strength is somebody that can take criticism, that can go out on a day like Sept. 11 and bring people together. And, you know, folks on my side like to use the term 'snowflake' when talking about people that get offended really easily — well, that's Donald Trump." 

Kinzinger said he "certainly" believes Trump to be weak, for being both easily offended and a fan of punching down. "I mean, he'll attack a radio host, for goodness sakes, when he was president of the United States. That to me, at least how I grew up ... that to me was always weakness."

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