On MSNBC tonight, 10 Republican presidential candidates will crowd a stage for a debate at the Ronald Reagan Presidential Library.

California Rep. Duncan Hunter has drawn one of the center lecterns, a small chunk of symbolism that may signal the beginning of his ascendancy.

The three GOP front-runners will be there. The job for the remaining seven is clear. They must position themselves to be the beneficiary of a top-three stumble. The question is: Who’s in the position of heir apparent to a loftier perch?

Mr. Hunter does not have John McCain’s fame, Rudy Giuliani’s razor wit or Mitt Romney’s matinee idol smoothness. But he also doesn’t have their baggage.

Mr. McCain’s struggles likely will continue. While he has been a courageous defender of the war, he looks tired and still faces a GOP base that cannot stomach his soft immigration stance and flat-out wrongness on campaign finance reform.

Mr. Giuliani’s poll leads are starting to shrink as voters wistfully wonder about the potential entry of Fred Thompson or Newt Gingrich. The former New York mayor has had some success at convincing skeptics that the liberal views he holds involve decisions made by mayors and state lawmakers, not by presidents. But can he withstand intensifying pressure from the right as the months pass?

Mr. Romney is making plenty of conservative noises of late, which has helped him rake in big dollars, if not big poll numbers. But some wonder if he is a convenient latecomer to those views, and there is the still-looming question of potential voter hesitancy over his Mormon faith.

So if an opening arises in the GOP top three, why should it be filled by Duncan Hunter? Because he is the best example of the no-nonsense unapologetic down-the-line conservative that many Republican voters say they are looking for.

With all due respect to Sam Brownback, Mike Huckabee, Ron Paul, Tom Tancredo, Jim Gilmore and Tommy Thompson (the other debate attendees), Mr. Hunter is the candidate whose days have been filled over recent years with the two most pressing issues America faces: immigration and the war on terror.

He is the ranking Republican and former chairman of the House Armed Services Committee, using that post as a megaphone to remind a soft, war-weary Congress (and nation) that the consequences of surrender in Iraq are bleak.

Even more boldly, he has focused often on the ludicrousness of judging America’s actions by the wildly fluctuating moral standards of “world opinion.” How many politicians have the guts to say we should do what is right and let the chips fall where they may?

This extends to treatment of detainees in wartime. As I spoke with Mr. Hunter on Monday, the most important part of former CIA Director George Tenet’s new book was already being largely ignored by the mainstream press: the part in which he guarantees that lives have been saved and plots stopped by particularly aggressive and creative interrogations.

Mr. Hunter joins the fray by sticking up for the horribly maligned men and women who serve at the Guantánamo Bay detainment camp, overseeing enemy combatants sworn to kill us who are in turn afforded the best food and medical care of their lives.

His immigration passions stem from serving since 1980 as San Diego’s congressman. His familiarity with the Mexican border sparked his passion to address our immigration problem with the most direct and effective method: a wall. Illegal border crossings and other crime are down as a result.

He spearheaded 60 miles of wall along his state’s border with Mexico and asserts that other states should follow suit. He is right again on another issue that leaves most of the GOP field hemming and hawing.

On issues from Iraq to Iran, from abortion to gun rights to free trade, Mr. Hunter appears to be the Reaganesque conservative missing from the top of the polls.

2008 may wind up as a year when Republicans embrace a different kind of candidate. It may be Mr. Giuliani’s nomination to lose. But if the party has the hunger some say it does for a return to a reliable, pragmatic conservatism in the Goldwater mold, tomorrow’s debate may be the beginning of a very interesting spring and summer for Duncan Hunter.

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