Ben Smith: “Obama spent much of his speech on a long defense of his own presidency, and condemnation of Republican governance.” “But Obama didn’t come to Nevada to make news, and he mostly didn’t. This is the box he’s in now. Even as he’s edged away from the tradition of post-presidential silence, there’s a more practical reason for his muted campaigning: He’s said to be afraid his presence would backfire, give Trump a foil, and energize the Republicans who Democrats hope will stay home in November.”