Claire McCaskill: This Aspect of Kamala Harris is Donald Trump's Kryptonite

Claire McCaskill argued on Tuesday's episode of Morning Joe that Kamala Harris's popularity and crowd sizes are like kryptonite for Donald Trump. 

Donald Trump wants the power of the presidency and wants to stay out of jail, but deep down, he also really wants to be liked. Kamala Harris seems to be quite popular right now and is holding massive rallies on a near daily basis.

And when Donald Trump sees these rallies, he not only knows that he has a tough road to winning the election against someone more popular than him, but he also knows that he has a tough road to winning the election against someone more popular than him. 

McCaskill said during a Tuesday segment, "It's been really fun, I think, for people who were very worried about Donald Trump getting in the Oval Office again. You know, what's really interesting about this is that when Trump is marginalized and cornered, his instincts are not to track to the middle or to become more reasonable in what he says. He really gets more and more bizarre."

Now the debate is a moment that could upset this momentum," the Missouri lawmaker continued, "but I'm trying to figure out what would really disrupt this momentum going forward for Kamala Harris, because I believe Trump will get worse and not better, when he is confronted with reality of these polls day after day, to say nothing of the size of the crowd, which is we all know, the Harris crowds are his kryptonite."