David Brooks:

We shouldn't be closing down the race so early into it, which is essentially I think what's going to happen, with like 40 percent of the delegates chosen.

Second, I think Sanders looks strong and California and Texas and a lot of the bigger states, though what Mark says about voters not being prepared like the other voters — I was in Watts and Compton and South Central L.A. last week, and I talked with 15 people.

I was saying, who's — this is a Latino African-American community. Who's making sparks in this community? And of those people, I'd say a bunch, maybe the majority, certainly, couldn't name the candidates.

Like, they were against Trump. They knew that. That was clear. But they hadn't clued in. Now, you ask about local politics, they have got a lot of opinions. And so the national politics swoops in and all of a sudden people have to make a view, but they have been focusing on, frankly, more important things in their lives.

I would make a call to Bill Clinton and Barack Obama. I think Bernie Sanders represents a challenge to their style of Democratic Party. And the only two people who can create unity in an anti-Sanders wing are Barack Obama and Bill Clinton.

And if they came in said, we're going to organize, so we don't divide the vote five or six ways, then they could be the only ones to do that. They're probably not going to do it. They're going to sit on the sidelines. But I do think, if they want to defend the Democratic Party as they understand it, this is the week.

This is the moment when they say, it's going to be Biden, and we're all going to work together, or it's going to be X, and we're all going to work together. I do think there has to be some leadership. Otherwise, it looks extremely likely to me that Bernie Sanders just walks away with it.