Only registered republicans and democrats can vote in today's presidential primary in New York State. And democrats will have more choices to make once inside the voting booth.

Everyone kind of knows what delegates are, they vote for a presidential candidate at the national convention. But many people aren't sure why you need to vote for a delegate who will vote on your behalf when you're already casting your vote in a popular election.

For the republicans, it's easy, because New York is winner take all for their delegates; whichever republican wins the popular vote gets all of New York’s 101 delegates. The delegates aren't listed on the ballot.

But on the democratic side, out of 232 delegates, 151 will be split based on the vote in each of the state's 29 congressional districts. The remaining 81 will be divided based on the statewide popular vote. If you didn't get that phd in mathematics, you might be a little confused. You're not alone; some poll workers say there were lots of questions today regarding the exact role of delegates. One local expert breaks it down for us.

"Democrats will see the names of the different candidates and they'll also see names of different delegates. Delegates are allocated in the congressional district in the state based on the number of votes for each candidate" Philip Klinkner of Hamilton College

Klinkner says there are no definites of course but it's more likely we'll see a clear frontrunner on the republican side if McCain finishes strong. Klinkner thinks the democratic contest might be too close to call in New York although he expects the media will want to declare a winner or frontrunner.

Polls are open until nine and of course if there's any confusion about the ballot just ask and election worker.