Concur on both counts. The latest New York thing - come on, guys, seriously? Nevertheless, it serves to differentiate, which is the purpose, I suppose. The Cruz birther thing was and remains an obvious attempt to distract the candidate from his message and frankly is better dealt with now than, say, in July. For all the heat it's generated I'm glad it came up now.
This sort of bickering can backfire. Yeb's public image isn't helped at all by playground banter; it's already suffering from a lack of gravitas, which is what anyone participating in this sort of thing risks.
Trump’s answer to Cruz’s insult on New York won Trump the nomination and Presidency. Cruz is horrible at debate. His 2nd grade answer to the birther stuff was silly too......your Mom......barf.