With 95.8 percent of the 1,774 precincts counted from the first-in-the-nation nominating process posted on The Des Moines Register Web site, Santorum, a former U.S. senator from Pennsylvania, and Romney, a former Massachusetts governor, were knotted at 24.6 percent, with 29,017 votes and 28,908 votes respectively. Paul, a congressman from Texas, was at 21.3 percent or 25,092 votes.
Rounding out the field were U.S. Rep. Michele Bachmann of Minnesota at 5.0 percent (5,916 votes); former Utah Gov. Jon Huntsman at 0.6 percent (702 votes, and "other," Georgia businessman Herman Cain and former Louisiana Gov. Buddy Roemer all at 0.1 percent or less.
The Boston Globe noted Iowa's multi-step caucus process makes Tuesday's results essentially a non-binding straw poll. The state will send 28 delegates to the party's national convention in Florida this summer, with 25 decided at the state convention in June and three more selected by the state GOP chair, national committeeman and national committeewoman.
Several polls have indicated as many as 40 percent of the state's voters were undecided as of Monday, The Hill reported.
In the race for the first brass ring of the 2012 primary season, several state and national polls indicated Romney, Paul and Santorum were the three to beat, with Santorum showing the greatest momentum.
Results must provide Gingrich, Perry, Bachmann and the rest a reason to campaign on as the race shifts from America's heartland to New Hampshire, South Carolina and Florida before the end of January.
Between 115,000 and 120,000 Iowa Republicans were expected to record their choices, GOP strategist John Stineman of West Des Moines told the Register.
While only registered Republicans can vote in the Iowa caucuses, anyone eligible to vote or registered with another party could opt to register as a Republican Tuesday and participate in the caucuses, state election officials said.
"I think we could have record caucus turnout, and I think that could be in large part with people who had affiliated themselves as independents and now will affiliate themselves as Republicans," Iowa Secretary of State Matt Schultz, a Republican supporting Santorum, told The Washington Post.
The issue isn't insignificant because recent polls in Iowa suggest Paul does well with unaffiliated voters, winning 42 percent of voters not aligned with either major political party in the most recent Register poll last week. Romney was a distant second with unaffiliated voters, collecting 19 percent.
"There's a very real chance that Mitt Romney will actually win the Republican vote on Tuesday night but lose the caucus because of Paul's overwhelming support from independents and Democrats," said Tom Jensen of Public Policy Polling, which estimates 20 percent to 25 percent of caucus-goers will be non-Republicans.