Presidential candidates launch their bids in different cities -- from Louisville to Lynchburg, Miami to Addison -- but, for many Republicans, the first stop on the campaign trail is the same: "Hannity."

In the last two months, four GOP hopefuls have given Sean Hannity dibs on their first interviews as candidates and been rewarded with hour-long "special events" on his primetime Fox News program. Others have tried to land an interview with the conservative host, campaign sources said, only to be turned down -- either because they had given their first interview to another media outlet, or because they weren't popular enough.

On Thursday, former Texas Gov. Rick Perry will become the fourth Republican to get an hour-long special on Hannity's program. Senators Rand Paul, Ted Cruz and Marco Rubio were all given the same hour-long special the night after they formally announced their bids.

For Republicans, Hannity provides instant access to the highly coveted conservative base. His show averaged more than 1.5 million viewers a night in May, according to the network's most recent ratings report. While that's lower than the viewership for "The O'Reilly Factor" or "The Kelly File," the bulk of Hannity's viewers are, like the host, reliably conservative. He also hosts a daily talk radio program that is second only to Rush Limbaugh in terms of listenership.

"Sean Hannity has a loyal following among the viewership of Fox News," Sergio Gor, a spokesperson for Paul, told the On Media blog. "He is one of the most influential voices among republican primary voters, and it doesn't hurt that with every year he's becoming an even greater lover of liberty."

Rick Tyler, a spokesperson for Cruz, said Hannity "has a big target audience and his questions are from a center-right perspective. In other words, he brings up the issues Republican primary voters are interested in."

Hannity was traveling back from his Perry interview taping on Thursday evening, and thus unavailable for comment.

Not every candidate gave their first interview to Hannity, of course. Some candidates have opted for other Fox News personalities -- Mike Huckabee went to Megyn Kelly, Lindsey Graham went to Greta Van Susteren -- while others have used bigger media platforms to announce their bids: Carly Fiorina on ABC's "Good Morning America," and Rick Santorum on ABC's "This Week with George Stephanopolous." 

But campaign sources said some candidates had sought out an interview with Hannity only to be turned down because it wasn't an exclusive or because Hannity didn't believe the candidate merited a full-hour of coverage. "Every candidate would love an hour of primetime coverage on Fox News," one campaign source said. "If you're running for president, you want that hour. Not everyone gets it."

Three Republican heavyweights have yet to announce: Jeb Bush, Scott Walker and Chris Christie. Surely, Hannity will be eager to land all three of those candidates. Whether or not they opt for the Hannity "special" will depend on their respective campaign strategies and relationships with the host. But for candidates like Bush who are still trying to win over the conservative base, an hour on Hannity may be just the ticket. It wouldn't be the first time, nor the second, that Bush had turned to Hannity to make inroads there.

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