The Birther charges against Cruz have no merit IMHO.
This will not prevent Liberal judges from entertaining them to gum up his transition if he wins.
You're correct, of course. But I gotta think that's not the point.
No, I think Trump is aiming mainly to catch the attention of the low-info voters, most of whom know nothing about the location of Cruz's birth.
So, now those voters will be wondering why in the world they should even think about voting for a guy born in Canada. And many of them won't vote for him.
Call it brilliant politics, call it cynical, call it dirty innuendo or whatever. But I believe Trump knows exactly what he is doing.