Updated 2:09 p.m. Eastern Time
Newt Gingrich and Ron Paul's slim hopes of winning the Republican presidential nomination depend primarily on their ability to triumph at a contested convention in August. The idea is that if front-runner Mitt Romney falls short of the 1,144 delegates he needs to secure the nomination outright before the convention, his rivals will seize the opportunity to win over the Republican faithful during the convention process.
That long-shot strategy depends on Gingrich and Paul actually getting on the convention ballot. And it now appears that may be a problem. The Atlanta-Journal Constitution has noticed a little-known rule - No. 40(b), to be exact - that would seem to keep the two candidates from being able to participate in a floor fight.
The rule was adopted in 2008, and here's what it says: "Each candidate for nomination for President of the United States and Vice President of the United States shall demonstrate the support of a plurality of the delegates from each of five (5) or more states, severally, prior to the presentation of the name of that candidate for nomination."
Gingrich has won a plurality in two states so far, South Carolina and Georgia; Paul has not won any states. The Republican National Convention confirms to CBS News that this means a candidate would not qualify for the first ballot at the convention unless they get, as the rule states, a plurality of delegates in five states.
On MSNBC's "The Daily Rundown" Wednesday morning, RNC Chairman Reince Preibus said the rule is "important."
"So when these candidates are adding up their delegates or when people out there have a particular issue that they would like to move at the convention, they had better make sure they at least have a plurality of five states to make these things happen," he said.
The Gingrich camp did not immediately respond to questions about how the rule affects their strategies. Paul campaign chairman Jesse Benton said he anticipated meeting the five-state threshold, saying in an email that "we are well positioned to carry WA, MN, AK, ND and ME among several others."
It's possible that even if Gingrich or Paul's delegates can't vote for their candidate on the first ballot, they could do so on subsequent ballots if Gingrich and/or Paul garners the support of a plurality of delegates from at least five states during the fight on the convention floor. Under Republican National Committee rules, Gingrich or Paul would need to be formally nominated after the first ballot for this to happen, and demonstrate their support in five states when this happens. It's an extremely unlikely scenario, though technically possible.
A related question: What happens to bound delegates if their candidate doesn't appear on the ballot? CBS News has contacted the four state Republican parties to explain what would happen to Gingrich and Paul's bound delegates if the candidates are not on the ballot; thus far only Mississippi Republican party has responded.
"[S]hould Gingrich not be on the first ballot, his delegates would be released in the same way that they would if he suspended his campaign," Communications Director Brett Kittredge said in an email.
With reporting by Rodney Hawkins.