When it comes to political drama like the unfolding 2008 presidential race, I am a big fan of the invisible hand theory. Similar to Adam Smith’s beliefs that some higher power influences economic behavior, I am absolutely certain that a hidden, lurking force manipulates the creation of multi-candidate fields.

Like a good screenwriter, the political invisible hand recognizes that each race needs frontrunners and long-shot underdogs. And a proper presidential field requires geographical balance. The current field needs a Southerner, for example. Ideology shapes the fields, too. When it comes to the Republican side of the ledger, there must be a conservative. Why, you ask, must there be a conservative? My answer is simple: because someone has to win the primary. The conservative almost always wins when two or more Republicans face each other. So this field needs a movement conservative. At least that’s what the invisible hand believes.

Two acknowledged candidates, Arizona Sen. John McCain and Massachusetts Gov. Mitt Romney, possess some conservative credentials, but neither of them seems particularly interested in being the “real” conservative. They are already moving to the center to win the general election, and this could be their undoing if a genuine conservative enters the fray.

So where can the invisible hand recruit a conservative standard-bearer? The loss of the majority in Congress pretty much eliminates congressional incumbents. And there don’t seem to be many incumbent governors that are logical choices either. Arkansas Gov. Mike Huckabee is one possibility. Colorado Gov. Bill Owens was a leading light — and could still be — if he showed interest. But people close to him say he won’t even consider running.

The invisible hand is running short on possibilities and, like a creative casting director, may have to get a little imaginative by going back to the future. Start with the thought that it’s hard to get anyone to run. You have to raise at least $50,000 a day (starting tomorrow, including Saturdays and Sundays). And it’s a brutal travel schedule, banging around the country from pillar to post during the long nomination quest. And then there’s the poking and prodding that comes to any presidential candidate. The media, party activists, and donors form a gauntlet that only fearless candidates dare run.

So where do we find someone like that, who’s also properly conservative? Two possibilities come to mind. Both have sterling conservative credentials and both have in the past shown they want to be president. They actually ran, perhaps before their appointed time. Maybe they should have waited for the invisible hand to give his official signal that it’s their turn.

Just in case the call is placed, I hope that former Texas Sen. Phil Gramm and former Vice President Dan Quayle stay close to the phone in the weeks ahead.

Gramm may have other presidential aspirations that get in the way. He’s rumored to be interested in the Texas A&M presidency recently vacated by incoming Defense Secretary Robert Gates. But he’s a ferocious fundraiser who’d really get conservatives in a lather if he decided to throw his hat into the ring.

Quayle is an interesting thought. When he abandoned the race in 1995 for health reasons, at 48 years of age, he told me that there would be six more presidential races before he was as old as Bob Dole, the 1996 nominee. So maybe he understood the wisdom of waiting your turn. Could this be his year?

Either one would be welcomed by most movement conservatives with open arms. Are there arguments to be made against them? Sure. But McCain and Romney — as well as Sen. Hillary Rodham Clinton (D-N.Y.) and all the other Democrats — have shortcomings too. But I am sure that Gramm and Quayle are big-name true-blue conservatives, and that’s what the invisible hand needs to get into this field — ASAP.

Hill is director of Hill Research Consultants, a Texas-based firm that has polled for GOP candidates and causes since 1988.