Republican Party candidates seeking to challenge U.S. President Barack Obama in 2012 face a highly anticipated test vote Saturday in Iowa.

The so-called “straw poll” held in the city of Ames is seen as a key test for the candidates seeking the Republican nomination.

On the ballot are nine candidates, including front-runner and former Massachusetts governor Mitt Romney, former House speaker Newt Gingrich and U.S. Representative and Tea Party favorite Michele Bachmann.

In an attempt to boost their chances, many of the candidates spent Friday campaigning at the Iowa State Fair, giving local voters a rare chance to get close and interact with them.

Texas Governor Rick Perry will soon be joining them on the campaign trail. He will formally enter the race for the nomination on Saturday while visiting South Carolina.

Perry is considered one of the more formidable candidates, with a strong record of job growth, and a record that can potentially appeal to both social and economic conservatives.

Surveys found most likely Republican primary voters plan to support Romney, with Perry next in line.

Another potential candidate, former Alaska governor and 2008 vice presidential candidate Sarah Palin, has not indicated whether she will run, so she is also not on the Iowa ballot on Saturday.