John Avlon captures the consensus:
Right now, Mitt Romney’s commanding lead in the polls is a reflection of the fact that he has the center-right all to himself in a crowded far-right field. He is essentially the default frontrunner. Huntsman’s entry will create competition for that demographic, boosted by the lack of enthusiasm for Romney.
Josh Green notes that Romney appears to be "moderating his image for the general electorate" while Huntsman is "making every effort to appeal to the right wing." Kevin Drum suspects that Huntsman is setting himself up for 2016:
[Running for president] just to set yourself up for a possible win four years down the road? That's some serious dedication. Huntsman must have a level of determination and self-control that makes Thomas Edison look like an indolent street urchin.
Or just doing what is required to be a Republican president.
(Photo: Republican Jon Huntsman waves as he arrives to a press conference to announce his bid for the presidency at Liberty State Park June 21, 2011 in Jersey City, New Jersey. Huntsman, until recently the U.S. ambassador to China under President Obama, emphasized his record as a two-term governor of Utah. By Spencer Platt/Getty Images)
The Dish 