WATCH: Morning Joe Explains How Nikki Haley is Quickening Trump's Mental Decline

This GOP sort of held a primary for the Republican nomination. The weird part was that the front-runner, Donald Trump, seemed completely disinterested in taking part. And the non-Trump candidates wouldn't say anything negative about him, instead they seemingly campaigned to be his running mate. 

Now, the primary season has come down to two candidates; Trump and Nikki Haley. Haley has recently opened up on Trump, referencing his constant gaffes and mental fitness. According to a Morning Joe panel, this is driving Trump crazy. 

Mika Brzezinski opined, "She has been able to make headway with that message. That, no, Donald Trump is not just crazy, he actually is senile too."

Brzezinski continued, "he's been making headway with that message, and she's gotten in some pretty good hits. Over the past — you know, since New Hampshire happened — what good hits has Donald Trump gotten in on Nikki Haley? He hasn't been able to attack her effectively. He hasn't been able to define her in the way he was with Ron DeSantis."

Joe Scarborough then weighed in, noting:

"He's in a position he's not usually in where he is not striking back as aggressively. He's got two women that have just, let's face it, they pounded him in the pocketbook, pounded him politically. So he's keeping his mouth shut on E. Jean Carroll who just won $83 million from him. Really, for the most part, not going after Nikki Haley as aggressively as he would want to because he's got his campaign people going, 'Please, please, the less you say, like the easier our job is, Donald. Just keep your mouth shut."