The 24-hour news cycle yielded one of its better sitcom interludes last week when Rand Paul went to Howard University, the historically black college, to tell its student body why it needed the Republican Party. The libertarian junior senator from Kentucky, at one point, asked for a show-of-hands from those who knew that most of the African Americans who founded the NAACP more than 100 years ago were Republican. When several dozen hands shot up, Paul insisted he wasn’t condescending to them, saying, “I don’t know what you know.” You won’t get a better title for this sitcom than that.

I wonder what would happen if you administered a similar quiz to a more demographically diverse multiplex audience after a screening of 42, Brian Helgeland’s rousing biopic about Jackie Robinson. How many would know that Robinson was a lifelong Republican? A few hands might go up, most from history geeks and older persons who’d brought their grandchildren to the movie. Then again, the story of Jackie Robinson’s post-baseball life is, to say the least, less triumphant than the one told by Helgeland’s movie. As Roger Kahn wrote in his classic 1972 book about the 1950s Brooklyn Dodgers, The Boys of Summer, Robinson’s career as a political activist “trails off into disappointments and conditional sentences.”...