...he will reap the benefits on March 1. Almost one-quarter of the available delegates are up for grabs that day, mostly in primaries in the Deep South. That already favors Cruz, not least because his home state of Texas offers the most delegates, but Rubio's slide will help him even more. In all of those Southern states but one, candidates must reach either 15 or 20 percent of the vote to receive any delegates at all, as we noted last week. Rubio was already only pulling about 10 percent several of those states. With his standing weakened and the so-called...