David Drucker performs some early electoral calculations for Washington Examiner readers.

Ted Cruz versus Donald Trump in Iowa would have clearly drawn battle lines.

Cruz would argue that he was the only true conservative in the race; Trump would counter that only a non-politician can be trusted to go to Washington and shake things up. The Texas senator might add that Trump has a history of supporting liberal positions and causes; the New York real estate mogul and reality television start might counter that only he has vowed to round up and deport all 11-12 million illegal immigrants.

But in the fluid campaign to woo Republican voters ahead of the Feb. 1 caucuses, the drama lies in determining what would have to happen for the Iowa battle to boil down to these two top presidential contenders. In the two most recent public surveys of likely Iowa caucus goers, Trump led the field, followed by Cruz. In the most recent available poll, conducted by Quinnipiac last month, Trump led Cruz by just 2 points.

Ben Carson, who until recently appeared to be in command in the Hawkeye State, could hold the key. The retired pediatric neurosurgeon is still among the most-liked candidates in the GOP nominating contest, and has been particularly strong among evangelical Christians, a crucial voting bloc. Whether they stick with him, or bolt to other candidates could impact the contest from top to bottom.

“I think the issue in Iowa is: What does Carson get?” Republican strategist Brad Todd told the Washington Examiner on Wednesday. “There’s a lot of game theory going on with Iowa caucus goers; they’re educated.”