WATCH: MSNBC's Mika perfectly explains the real reason Trump keeps 'bullying' Hillary Clinton

MSNBC's Mika Brzezinski examined President Donald Trump's apparent obsession with former rival Hillary Clinton -- and found he maybe just doesn't know anything else to talk about.

She and her "Morning Joe" co-host Joe Scarborough watched the president's news conference Wednesday where he insisted there had been "no collusion" between his campaign and Russia, and insisted his Democratic rival was guilty of crimes his associates had been accused of committing.

"That is so pathetic and sad that he keeps going back to campaign talking about Hillary Clinton and wind mills," Scarborough said. "This is -- well, we were talking about football before. Does anybody here think that (Alabama coach) Nick Saban is going to be obsessing over the Georgia Bulldogs a year from now or six months from now?"

Brzezinski agreed Saban, whose team won the national championship over Georgia earlier this week, was almost certainly not thinking of his vanquished rival a few days later.

"Do you think a CEO that takes over another company and successfully takes over another company at six months after is thinking how to move his or her company forward?" Scarborough said. "Or are they obsessing over how they got the better company they took over. This is a real problem and a sickness with this guy. I'm not saying mental sickness with this guy, it's a real problem."

Brzezinski walked through two possible explanations for Trump's obsession with Clinton.

"One is he is obsessed with her, and that would be kind of strange and maybe something psychiatric," Brzezinski said. "Also it may be, and this we've seen with people that feel they don't have capacity or command of the issues. They go to things that they can handle, so he can handle bullying Hillary Clinton, someone he beat, because that will fill time instead of actually having to talk about the content."

Scarborough recalled the interview Trump gave in March 2016 to the Washington Post editorial board, when he named George Papadopoulos to his foreign policy team, and kept talking about his own hands.

"You read the transcript, it was shocking," Scarborough said. "'I have the most beautiful hands, people come up to me -- your hands, they're very strong, big, beautiful hands.' He kept going on and on. I was reading, I said to Mika, 'Oh my god, he has completely lost his mind.' She said, 'No, he hasn't -- he is running out the clock because he doesn't want them to ask him questions about policy, because he knows nothing about policy.'"