Race For Presidential Nominations Heat Up With One Week To Go Until PA Primary

By Jim Melwert

PHILADELPHIA (CBS) -- As the presidential primaries grind on, all eyes are about to shift to Pennsylvania, which holds its primary election one week from today.

On the Republican side, Pennsylvania carries 71 delegates, but because of how those delegates are awarded, voters need to study up -- not only on candidates for office, they should also know who each of the delegates back.

Seventeen of Pennsylvania's 71 GOP delegates will be beholden to the candidate who gets the most votes next Tuesday, but only for the first ballot at July's republican convention.

That means 54 delegates will be elected – three from each of the 18 congressional districts – and they can vote for whichever candidate they choose at the convention.

Ted Cruz's Pennsylvania campaign chairman Lowman Henry, says voters will need to do their homework because the ballot will not list which candidate the delegates back:

"So voters have to know when they go into the polling place for whom the delegates are pledged to support."

Political analysts say Cruz appears to have the best ground game as far as lining up delegates in Pennsylvania, and Henry says they to working to inform voters which delegates are backing Cruz.

Henry says these rules have been around for more than 50-years, but it's rare the nomination is still up in the air when Pennsylvania goes to the polls. The last contested convention was in 1976 when Gerald Ford topped Ronald Reagan.

The state republican party recommends voters reach out the campaign of the candidate they support to learn which delegates they should vote for. Or delegates can be reached directly as contact information is available on the Pennsylvania department of state's website.