Essential qualities

THIS WAS a debate that highlighted the essence of the top three candidates.

Former Massachusetts Governor Mitt Romney displayed the verbal dexterity that renders him such a slick performer. Asked if, knowing what we know now, invading Iraq was a mistake, Romney slipped the surly bonds of the query. The question was a null set, a non sequitur, said he. (Aha!)

He deflected well. Yes, he conceded, he had once supported abortion rights, but he had had an epiphany. Sure, he formerly thought gays should be able to serve openly in the military, but he had been wrong. His enforce-the-existing-law immigration answer will surely please the base -- and he neatly used a gibe from Duncan Hunter to lay claim to Ronald Reagan's political legacy.

Former New York Mayor Rudy Giuliani had no truck with that sort of fancy footwork. He confronted the Iraq question with his trademark bulldozer bluntness -- and a seeming inability to draw important distinctions.

"It's unthinkable that you would leave Saddam Hussein in charge of Iraq and be able to fight the war on terror," he said. No matter that Iraq wasn't part of the 9/11 attacks and didn't have operatives ties with Al Qaeda. Giuliani, again, rolled it all into one ball.

The debate started poorly for Senator John McCain of Arizona, who was left to concede that he hadn't read the classified National Intelligence Estimate on Iraq, to defend George W. Bush's troop surge in Iraq, and to argue for an immigration bill unpopular with conservatives -- and the steady target of his rivals. And yet, by evening's end, one had to admire McCain's grim willingness to stick by his principles.

His two best moments came in his heartfelt answer to a questioner who had lost her brother in Iraq, and his willingness to remind everyone that Spanish speakers had died for this country in both Vietnam and Iraq.

Bottom line: Romney was most polished -- but McCain seemed most principled.

Scot Lehigh's e-mail address is lehigh@globe.com.