Which you immediately follow with your own opinions and anecdote. No sources cited. Nice work!
I say he "could" have a problem, because, from the articles I have read, it is possible the Massachusetts law may have a significant loophole. The artcles seem to say that he can avoid the Massachusetts tax by keeping the boat in Rhode Island for 6 months and then bringing it to Massachusetts. This would be unusual. Normally what happens when you bring a boat (or car) to a new state is that you have to pay the excise tax but get a credit for whatever sales or excise tax you paid in the previous state. This would mean Kerry would have to pay the whole tax, since he paid zero in Rhode Island. If Massachusetts really lets you bring a boat in tax-free after 6 months, that is a gaping loophole. My guess is that the articles are simply poorly written and that this is not the case, but I don't know whether that is so.