Writing at the Washington Post, Todd Zywicki speculates about the fact that Trump seems to do best in open primaries:
Following the South Carolina primary, an interesting article by Michael Harrington went around Facebook that speculated that Donald Trump’s victory in the South Carolina primary was attributable to Democrats voting in the Republican (open) primary. One of the good things about Harrington’s article is that he put out a testable hypothesis — that turnout in the Democratic primary a few days later would be less than 390,000. In fact, it was 367,000. Harrington concludes that had South Carolina had a closed primary, Ted Cruz would have won the primary there…. The fact that his prediction was borne out adds some independent verification to his thesis. So that got me to thinking.
If true, why does this matter? Because so far the primary calendar has been heavily tilted toward open primaries. But there have been four closed elections: the Iowa caucus, the Nevada caucus, and Super Tuesday’s Oklahoma primary and Alaska caucus. Ted Cruz won three of those four closed elections.
So here’s where it potentially gets interesting. Although the media are looking forward to March 15, this Saturday (March 5) there are four Republican primaries/caucuses: Kansas, Kentucky, Louisiana and Maine. All are closed.…
The four closed primaries and caucuses this Saturday could be very interesting to watch, particularly to see whether Trump can maintain his momentum in closed primary states where he will have to appeal to the traditional Republican base. I haven’t gone through the remainder of the states to calculate in detail how many delegates will be selected through this series of closed primaries and whether those are enough to win. Trump also might start winning closed primaries and caucuses. But this has been his Achilles heel so far.