Once the meaningless inquisition about loose semantics and questionable acquaintances was done, Wednesday night’s debate between Barack Obama and Hillary Clinton got interesting.Granted, it’s likely that only the most intrepid viewers made it to the Promised Land of actual substance. For some reason, ABC News moderators Charles Gibson and George Stephanopoulos — smart and skilled interviewers who, to put it mildly, had an off night — spent what seemed like an eon grilling Obama and (to a lesser extent) Clinton about verbal gaffes they had already corrected and problematic entanglements they had already disentangled. You know the litany: Rev. Jeremiah Wright, the “bitter” working class, sniper fire in Bosnia, blah blah blah.I’m guessing public regard for the media’s role in our democracy was not greatly enhanced.But for viewers who kept wading until they got to the other side of the swamp, this turned out to be one of the better debates of the campaign — and that’s saying something, since it was the 21st such encounter for Clinton and Obama. One imagines they’re a little tired of the drill, and of each other. No wonder they were so manifestly uninterested when Gibson pressed them to agree to a joint ticket.He should have pressed instead for more explanation of Clinton’s proposal to counter the Iranian government’s nuclear ambitions with a broad shield of U.S. nuclear deterrence — protecting not just Israel but other countries in the region as well, such as Saudi Arabia. This strikes me as the kind of big, complicated idea someone should have asked Clinton to explain further. That didn’t happen.In the looking-glass world of nuclear weapons theory, a U.S. pledge to nuke Iran if it ever nuked Israel could make officials in both countries breathe easier. One potential benefit would be to lessen the possibility that Israeli leaders, fearing an Iranian attack that might eliminate Israel’s ability to retaliate, would order a pre-emptive strike.But is it wise to specify America’s reaction to a threat that does not yet exist? Iran, after all, is years away from being able to build, let alone deploy, a nuclear bomb. What impact would such a U.S. declaration have on diplomatic attempts — which Clinton says she will make — to engage Iran in productive negotiations? And wouldn’t Clinton’s proposal just further George W. Bush’s policy of deepening the fault lines in the Middle East, rather than trying to mend them?Another newsy tidbit was the declaration by Obama — a longtime gun-control advocate who has taught constitutional law — that he believes “as a general principle” that the Second Amendment guarantees citizens an individual right to keep and bear arms. The Supreme Court last ruled on the question in 1939, holding that the amendment assures a collective right that applies to the states. Obama’s interpretation has considerable support among legal scholars — but is strongly opposed by many liberal advocates of gun control.It also qualified as news that, when asked about soaring gasoline prices, Clinton vowed to investigate what she believes is “manipulation” of the market. She added that she would recommend releasing some oil from the nation’s strategic reserve. Surely she understands that the price of oil is set globally and reflects such factors as soaring demand from China and the weakness of the dollar. What does her proposed remedy have to do with the price consumers pay at the gas pump?We also saw that Democrats have finally learned to pander on the issue of taxes as effectively as Republicans. Clinton promised not to raise a single tax for the middle class; Obama went her one better, pledging to cut taxes for the middle class. Of course, the asterisk is in how you define “middle class” and what you call a “tax.” But casual listeners might have wondered which party they belonged to.And Obama threatened to make news, but didn’t quite, when the subject turned to affirmative action. He walked to the brink of a clear declaration that all affirmative action programs taking race into account should also have to consider income — but didn’t quite take the leap.All of this might not have been electric, but it was illuminating. I think these issues may even be more important than whether Obama once sat on a charity board with an aging former member of a 1960s radical group — or even whether Bill Clinton commuted the prison sentences of two other radicals.Send Eugene Robinson e-mail at email@example.com.