The Volokh Conspiracy
"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. I don’t know him and the author seems to be anti-Trump based on other things he has written — but the fact that his prediction was borne out adds some independent verification to his thesis. So that got me to thinking."