According to CNN's Jake Tapper, Donald Trump is currently living inside Barack Obama's head, constantly uppermost in his thoughts, no matter the situation. And in this case the situation was the press conference yesterday at the North American Leaders Conference in Ottawa, Canada. During CNN's The Lead, Wednesday, Tapper explained:

PRESIDENT OBAMA: So, let's just be clear that somebody who labels us vs. them or engages in rhetoric about how we're going to look after ourselves and take it to the other guy, that's not the definition of populism. Sorry. This is one of the prerogatives of when you're at the end of your term. You just kind of -- you go on these occasional rants.

JAKE TAPPER: President Obama just wrapping a news conference with Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto at the North American Leaders Summit in Ottawa, Canada. Let's talk about this, the president speaking quite a bit about trade, quite a bit about accomplishments he wants to achieve with his Mexican and Canadian counterparts, and quite a bit about presumptive Republican presidential nominee Donald Trump.

Joining me to talk about this all, CNN chief political correspondent Dana Bash, CNN senior political reporter Nia-Malika Henderson, CNN senior Washington correspondent Jeff Zeleny, and joining us from New York, CNN chief political analyst Gloria Borger. Gloria, let me start with you.

It is one of the grandest ironies of this political year is that a giant real estate developer in New York is currently living rent-free in President Obama's head. Whatever the topic is, President Obama is eager to go after the presumptive Republican presidential nominee, whether the topic is ISIS after the Orlando shootings, or the topic is trade, or, in this case, the question was about clean energy, and he -- President Obama wanted to give a lesson as to what populism truly is.