http://www.nytimes.com/2012/04/15/bu...3&ref=business

Well... not explicitly. It's an interesting article overall, and toward the end he says --

Whether competition among governments is good or bad comes down to the philosophical questions of what you want government to do and how much you fear government power. If the government’s job is merely to provide services, like roads, schools and courts, competition among governmental producers may be as good a discipline as competition among private producers. But if government’s job is also to remedy many of life’s inequities, you may want a stronger centralized government, unchecked by competition.


These are two fundamentally different visions. The next election, and to some degree every election, is about which one voters find more compelling.
Maybe Mankiw is not intending to endorse Obama. But - since it has long been acknowledged by all but the most parsimonious of Libertarians that part of government's role is, indeed, to remedy some of life's inequities - and any polling you can dig up will likely confirm that... maybe what he is actually doing is offering a forecast of Obama's re-election.