[rawr]

"Since we’re spending so much time and money to promote this phrase, we just want to make sure someone doesn’t say we can’t use it."

That seems like a reasonable argument. Also, IANAL but if I'm not mistaken just because somebody has a trademark for something doesn't mean that it's necessary enforceable.

[andrewmccall]

It sounds like a reasonable argument, but it also gives them the right to turn around and tell someone else they can't use it and for some of these really common expressions that's just not right.

Also if they're already using it and someone else tries to trade mark it and prevent them from doing so I would expect Harvard can come up with an expert witness or two and put a stop to it.

So I'm afraid the argument seems reasonable, but doesn't hold water.