This morning, former Arkansas Gov. Mike Huckabee announced his entry into the contest for the GOP's 2016 presidential nomination. He's already the third person this week to join a field that is growing so large, one wonders if the first primary debate in August won't be divided into two "heats," a la preliminaries in track or swimming, to accommodate a crowd that could be well into the teens by then.

Huckabee, who spoke today in the hometown of Hope, Ark., he shares with Bill Clinton, ran third behind John McCain and Mitt Romney in the 2008 primary. He was expected to try again in 2012 but declined to do so. Although he retains a good bit of goodwill with social conservatives and has amplified his profile with his "Huckabee" show that ran on Fox News for more than six years, one wonders if his moment hasn't already passed.

Monday's announcements brought two decided long shots into the field: Carly Fiorina and Ben Carson. Fiorina, the former CEO of Hewlett-Packard whose only political experience is losing a 2010 Senate race in California, argues she's the best choice in large part because she would neutralize expected Democratic nominee Hillary Clinton's strategy of "playing the gender card" in the general election.

Carson, a celebrated neurosurgeon who leaped to political prominence by criticizing Obamacare at a national prayer breakfast while President Obama sat just a few feet away, launched his campaign at an event in Detroit, complete with a gospel choir's rendition of Eminem's "Lose Yourself" and an a capella rendition of "The Battle Hymn of the Republic." As you may have surmised, Carson intends to present himself as anything but your typical politician .

There are a number of politicians more seasoned than Carson and Fiorina -- and, in most cases, more contemporary than Huckabee -- already in the race or exploring an entry. There are current governors Chris Christie, Bobby Jindal and Scott Walker, current senators Ted Cruz, Lindsey Graham, Rand Paul and Marco Rubio, three-term Texas Gov. Rick Perry, two-term Florida Gov. Jeb Bush, plus former senator and 2012 runner-up Rick Santorum. So the question is: Which candidate, if any, of the trio that joined this week has staying power?

Let's put it to y'all, the voting public, in one of our periodic, if not scientific, polls. Who among Carson, Fiorina and Huckabee will be in the race the longest ... or possibly even win it? Vote below, and explain your choice in the comment thread.