INDIANAPOLIS, Ind. — Eric Trump, son of the presidential candidate, tweeted out today that Ted Cruz’s selection of Carly Fiorina “is truly one of the greatest acts of desperation I have ever seen.” This is true, of course, and even Cruz had to admit that it was “unusual to make the announcement as early as we are doing now.” But however unconventional it is, the only thing that matters is whether it works.

Purdue student Kyle Rice told me he’d made the trip down from West Lafayette to see Cruz speak (with Fiorina as a bonus surprise) because Cruz was “the only one who can stop Donald Trump.” And he wasn’t the only one attending the rally to bring this up unasked. But Cruz’s ability to do that is now in serious doubt. The math requires of him both a victory in Indiana next Tuesday and a very strong performance — possibly even an outright victory — in California.