Republicans Iowa
New Jersey Governor Chris Christie delivers his state of the state address at the New Jersey State House in Trenton, New Jersey, in this file photo taken January 13, 2015. Jumping in while potential rivals Jeb Bush and Mitt Romney are absent, Chris Christie will try to grab the spotlight in Iowa on Saturday at the first big gathering of likely 2016 Republican presidential contenders. REUTERS/Mike Segar/

DES MOINES (Reuters) - For Republicans, the long road to the 2016 presidential election begins in earnest on Saturday in Iowa when a group of potential candidates compete for support among conservatives in the state that will hold the country's first nominating contest.

As many as eight possible candidates are to take part in the Iowa Freedom Summit, a marathon day of back-to-back speeches organized by Iowa's conservative Republican Steve King, a member of the U.S. House of Representatives.

“There are a half a dozen candidates, plus or minus a little bit, that I would put their names in a hat and draw one out and be really happy as a replacement to the president we have today,” King told ABC News.

The key names to watch are a pair of governors, Chris Christie of New Jersey and Scott Walker of Wisconsin.

Christie is viewed skeptically by many conservatives, and how he crafts his message here could be critical. Many Republicans see Walker as a person to watch in spite of the early attention on the potential candidacies of Mitt Romney, the 2012 nominee, and former Florida Governor Jeb Bush.

There are a variety of other people who will be at the event and who could emerge as major 2016 players, such as former Texas Governor Rick Perry, who ran for the nomination and lost in 2012, and former Arkansas Governor Mike Huckabee, who won Iowa in 2008 but lost the nomination.

Texas Senator Ted Cruz will also speak along with former Hewlett-Packard Co Chief Executive Officer Carly Fiorina, physician Ben Carson and former Pennsylvania Senator Rick Santorum.

Steering clear of this event are Bush, Romney, Florida Senator Marco Rubio and Kentucky Senator Rand Paul.

Iowa holds the first nominating contest of 2016 when Republicans and Democrats gather early next year for caucuses. Republicans here have not picked the eventual nominee since they went for George W. Bush in 2004. But the caucuses do serve a valuable role in winnowing the field.

"This will serve as sort of the unofficial kickoff to the Iowa caucus season for 2016," said Tim Albrecht, an Iowa Republican strategist. "It's a great first look at how potential candidates stack up against each other."

The event, he added, will help Iowa Republicans get a feel for who has "a vision for America's role in the world, versus those who followed the TV cameras here."

On Sunday, Cruz will join Rubio and Paul in Palm Springs, California, where about 450 individuals are attending a winter “seminar” organized by a network of groups founded by brothers Charles and David Koch.

(Additional reporting by Amanda Becker in Washington; Editing by Lisa Shumaker)