This was the week that Republican presidential hopefuls finally realized that their only hope of beating Donald Trump was to actually campaign against him.
On Tuesday, we'll start finding out if their move came too late.
Good afternoon, I'm David Lauter, Washington Bureau chief. Welcome to the Friday edition of our Essential Politics newsletter, in which we look at the events of the week in the presidential campaign and highlight some particularly insightful stories.
Rubio, in particular, has been the favorite of many establishment Republicans, but as Lisa Mascaro noted, he has the huge disadvantage in that even his supporters can't name a single state he may be able to win. And, as Trump showed Friday afternoon by unveiling an endorsement from New Jersey Gov. Chris Christie, his current lead in the race gives him a tremendous advantage: He can unveil tactical maneuvers at any point to try to gain maximum publicity or squelch whatever momentum one of his rivals can generate.
"I got nothing against him," 76-year-old James Brown said of Sanders. "I don't know that much about him."
For coverage of Vice President Joe Biden's speech and other news from the California Democratic Convention this weekend, visit our Essential Politics live blog.