Rick Santorum may be ineligible for some delegates in his home state's of Pennsylvania's April 24 primary, possibly pointing to more of his organizational troubles.

The Allentown Morning Call reported in March that Santorum had failed to field a full slate of delegates, as he had in Illinois and Ohio. "The No. 1 goal is to make sure you can get on the ballot, which is what the Santorum campaign really focused on," Santorum state political director Brian Nutt acknowledged to the paper.

No one really knows how many delegates Santorum can win in Pennsylvania. Here's why:

Most of Pennsylvania's 72 delegates will be elected directly on primary ballots, and delegate-candidates do not have to say which presidential candidate they support. Pennsylvania's delegates are not "awarded" by the statewide vote; nor are there "Santorum delegates" or "Romney delegates" presented to the state elections board, as in Illinois. And they're all allowed to support whomever they prefer at the Republican National Convention.

This makes winning delegates a virtual "crapshoot," as state political experts have said. It comes down to 1) encouraging locally well-known supporters to run, and 2) flooding the congressional-district ballots with friendly delegates.

"We're not really sure how many people Rick has," said a prominent Romney supporter who's helping the campaign organize in Pennsylvania. This Romney organizer said the campaign hopes to split delegates 50/50 with Santorum, while Santorum will probably win the statewide vote-meaning the Romney campaign thinks it has some advantage over Santorum in the delegate race. The Romney campaign is currently trying to persuade delegates, without knowing whom they support.

"There are candidates who have said, on the record, 'I will support the winner of the congressional district,'" said G. Terry Madonna, director of the Franklin & Marshall College Center for Politics and Public Affairs, who also directs the college's political polling. "Some have said, 'We're not supporting anyone' … Some have said, 'I'm not telling you.'"

Given those uncertainties, it's difficult to tell how successfully Santorum's campaign encouraged his supporters to run. And even if it did poorly, a chunk of undecided delegates will likely back him if he wins the state or their congressional districts.

Pennsylvania Republicans will elect 59 delegates on congressional-district ballots, and the state party will select another 10 unbound delegates, in addition to the state's three RNC superdelegates