Who advanced in Fox Business's debate in North Charleston? Not Ben Carson, who was pleasant but largely irrelevant. Not John Kasich, who curbed his manic tendency but relied too much, at least for this election cycle, on issues that strike today's voters as antique; very few know what his references to the Central America controversies of the 1980s were about.

The two candidates who are statistically tied for the lead in Iowa polls — Donald Trump and Ted Cruz — each had a high point and a low point in attacks on each other.

Cruz's high point was over the issue of Cruz's status as a natural-born citizen. Cruz nailed this, with a show of good humor in which he almost maintained his previous posture of not attacking Trump. Trump was even booed repeatedly by the audience, which perhaps some Iowa voters will dismiss as made up of "establishment" Republicans, but which seemed pretty devastating.

But Trump came back later with what appeared to be a heartfelt response to Cruz's recent charge that he embodies "New York values." Trump brought back to life those days when all of America had no doubt that the whole country had been attacked when New York was attacked on September 11, 2001.

In effect, both candidates were hurt by their cheap shot attacks on each other — Trump's suggestion that Cruz might be disqualified from the presidency (which has no substance) and Cruz's suggestion that Trump is some kind of New York liberal (which he may well be on some issues, but Cruz provided no specifics).

Which one came out ahead? Not clear, at least to me. Both, by the way, struck strong notes in their indignation at the spectacle of American sailors humiliated by the Iranians.

The New Hampshire fight, for what appears now to be second place in the first-in-the-nation primary, was three-sided, among Cruz, Marco Rubio and Chris Christie. Christie made strong points in behalf of himself by attacking what he termed the Obama-Clinton policies and actions. I think he made less impact by his complaints about supposed squabbling between "two backbench senators."

Rubio and Cruz had their strongest interchanges on immigration, on which Rubio parried adroitly (though still on the defensive) from his support of the Gang of Eight bill in 2013, and on taxes, in which I think Rubio succeeded in sowing doubts about Cruz's VAT-like tax, whose details are dangerously unfamiliar to voters.

Rubio was not as pleasant and likeable as in previous debates, but his strong riffs on foreign policy and gun control may work to his advantage. As the obvious likely target of several other candidates, he was largely though not completely successful in keeping the focus on his attacks on President Obama.