CNN

AMES, Iowa (CNN)– Voting is underway in the first crucial Republican straw poll contest of the 2008 presidential campaign season. The first ballots were cast at 10am CT here on the campus of Iowa State University in Ames. Voting will last until 6pm local time and results will be announced one hour later.

Voters need to prove they are Iowa residents and need to pay a $35 entrance fee. Many of the campaigns are busing in their supporters and paying for their entrance fees. But the ballots are cast in secret so there is no guarantee on how people will vote, even if they are bused in and their entrance fees paid for by certain campaigns.

After they cast their ballots, voters need to dip their thumbs in indelible ink, similar to the kind used in the Iraqi national elections. This is supposed to prevent people from voting more than once.

Mitt Romney is expected to win today’s straw poll. The big question right now is by how much the former Massachusetts Governor will win. The top three GOP contenders in the national polls, former New York City Mayor Rudy Giuliani, former Senator from Tennessee Fred Thompson, who’s yet to announce he’s running for President, and Senator from Arizona John McCain, are not actively taking part in today’s straw poll.

The other big question today is which of the second tier candidates will come in second. Former Arkansas Governor Mike Huckabee, Senator from Kansas Sam Brownback, and former Wisconsin Governor and Bush Cabinet Secretary Tommy Thompson are all gunning hard for capturing second place. Congressmen Duncan Hunter and Ron Paul and Tom Tancredo are also here today and hoping for a strong finish.

There’s the possibility that some of these second and third tier candidates may drop out of the race for the White House if they don’t perform well in today’s straw poll.

– CNN Deputy Political Director Paul Steinhauser