This is pretty pathetic, even for a presidential campaign. Those legislators, and the voters they're pandering to, don't really know what they're talking about. Mae Beavers, a Tennessee state senator, has introduced a bill that would require a "long-form birth certificate" from 2012 candidates. She appeared on a radio show to discuss it and was asked what a "long-form birth certificate" was. She didn't know; she had just modeled the bill after what other states had done.
What does someone like Pawlenty have to gain when he dismisses all of this? Quite a lot, actually. Millions of Republicans may doubt Obama's citizenship—but millions more don't, or don't care. Many of the Republicans who do have doubts don't actually know or think that Obama should be kicked out of office on a technicality.
The Republicans who can shape elite opinion—this does not include Corsi—hate even thinking about this. If an investigation proved that Obama had gotten into Columbia and Harvard Law with mediocre grades, he might only win as many presidential elections as George W. Bush. Lots of Republicans think that birtherism is a good way for the White House to make their party look crazy.
With his definitive statement, Pawlenty appeals to those Republicans. He appeals to the political media, too. He's jumped one of the lowest bars in politics—but he's jumped it, and some other Republicans still haven't, or won't. Pawlenty wins a stamp of approval—not crazy!—that's incredibly easy to earn. Soon some other candidates will go for that stamp. They have a lot of time. The birthers aren't going anywhere.