Trump suggested shooting protesters, missile strikes in Mexico ...

But we begin tonight with the former defense secretary's thoughts on Russia's war in Ukraine.Norah O'Donnell: Overall, how would you grade President Biden and his administration's-- performance in terms of Ukraine?Mark Esper: It's mixed. I don't understand the reluctance to provide-- the Ukrainians with MiGs Norah O'Donnell: Fighter jets.Mark Esper: Fighter jets, that's right. Norah O'Donnell: Is there any scenario where President Putin could take those regions and then just declare victory?Mark Esper: Absolutely, absolutely. Norah O'Donnell: You had to keep pressing President Trump to release $250 million in aid to Ukraine?Mark Esper: Yes, it would be an argument after an argument. Dangerous things that could have taken the country in-- in a dark direction.Norah O'Donnell: What kind of terrible things did you prevent?Mark Esper: At various times-- during the-- certainly the last year of the administration, you know, folks in the White House are proposing to take military action against Venezuela. And so, as we went through the next five to six months, that became the metric by which we would measure things.Esper told us he had reason to be concerned, not just about an unnecessary military conflict with an adversary but with one of our closest neighbors and largest trading partners.Mark Esper: The president pulls me aside on at least a couple of occasions and suggests that maybe we have the U.S. military shoot missiles into Mexico-- Norah O'Donnell: Shoot missiles into Mexico for what?Mark Esper:  He would say to-- to go after the cartels. Did President Trump really say, "No one would know it was us?"Mark Esper: Yes. Yes. At a meeting the next morning, Esper told us, the commander-in-chief was on the verge of ordering 10,000 active-duty troops into the streets of the Capital.Norah O'Donnell: What was the most disturbing thing that the president said during that meeting on June 1st?Mark Esper: The president is ranting at-- at the room. Norah O'Donnell: What specifically was he suggesting that the U.S. military should do to these protesters?Mark Esper: He says, "Can't you just shoot them? And it-- it just dawned on me at that point in time that we'd been duped.Norah O'Donnell: Duped how?Mark Esper: This is a pol-- this is now a political stunt, right? He says he was sure Donald Trump would fire him.Norah O'Donnell: Why did you think he would fire you?Mark Esper: Because I publicly rebuked him. And what I would learn later is-- at the White House is he thought I took away his authority to invoke the Insurrection Act. He did not believe that he had the authority to impose it.Norah O'Donnell: Politically, you might have.Mark Esper: I suppose at a political level, I-- I did.