Keeler: Joe Biden and Paul Ryan debate policy with vigor

Once they shifted to domestic issues, with all the accompanying numbers, the punches started flying faster.

In sharp contrast to Obama’s rope-a-dope strategy, Biden and Ryan are exchanging punches, close in, and smiling the whole time. Rather than take notes or look down, Biden reacted instantly, so instantly that it got under Ryan's skin. So he got off a good counterpunch: “Mr. Vice President, I know you’re under a lot of duress to make up for lost ground, but people would be better served if we didn’t stop interrupting each other.” But Biden clearly felt he couldn't let anything Ryan said go unchallenged.

Biden was passionate in his opening salvo on unemployment, recalling Romney’s opposition to the rescue of the auto companies—notwithstanding Ryan’s description of Romney as "a car guy"—the 47 percent comment and the specter of Grover Norquist, the right-wing anti-tax guru who has frightened legions of Republicans into signing a no-new-taxes-ever pledge. Instead, he said, Romney-Ryan should be signing a pledge to the middle class. “It’s about time they took some responsibility.”

Ryan got off a good zinger in saying to the gaffe-prone veep that sometimes things don’t come out of your mouth the right way. But moments later, Ryan was repeating that semi-falsehood about Democrats controlling both the House and the Senate, plus the White House. Yes, for about two nanoseconds, and then the Democrats lost their 60-vote filibuster-proof majority, and the Republicans used the filibuster dozens of times to block action.

When they got into the flurry of rhetorical punches on Medicare, Ryan's best line was: "They got caught with their hands in the cookie jar, turning Medicare into a piggybank for Obamacare." But Biden counter-punched with: "If they just allowed Medicare to bargain for drugs like Medicaid can, it would save $150 billion."

But, boy, did they ever get deep into the weeds on the various tax-cut plans.

But Ryan dodged yet again when the moderator tried to nail him down on whether he does or does not have the specifics on their 20 percent across-the-board tax cut which prices out at $5 trillion—you know, the one that Romney more or less denied he'd be doing in the opening debate. "Six studies have verified that this math adds up." Ryan said. It all boiled down to this exchange: Biden: "Not mathematically possible." Ryan: "It is mathematically possible."

In response to the moderator's question on big-ticket deficit-cutting items, Biden didn't offer a lot, but he made pretty clear what the top line is: "Just let the taxes expire like they're supposed to on those millionaires. They don't need it, Martha."

These two men offered at least as many numbers as the top of the ticket, but the energy level and response time was so much higher than Obama-Romney were able to summon.