MANCHESTER, N.H. — Sen. Marco Rubio’s Saturday night performance in the Republican presidential debate will be remembered for the fact that he repeated the same point over and over rather than for the underlying substance of the point he was trying to make. But the thing is, he was trying to make a tricky argument in the first place.

To recap, Rubio was asked to respond to attacks that he’s not ready to be president, because just like President Obama was when elected, he’s a first term senator.