There are two ways to score a vice presidential debate: 1. Who looks ready to be president? 2. Who did a better job advancing his boss’s chances to be elected? On both accounts, Vice President Biden won — not by knockout, but on points.

Paul Ryan looked and sounded callow, from his first nervous sip of water. Ryan couldn’t have gotten a better first question on the Libyan embassy violence. He gave a specific, credible answer; but on rebuttal, Biden took it to a broader frame, outlining the Obama administration’s foreign policy successes. The Syrian discussion went for awhile, and Ryan gave the Republican talking points skillfully. Biden countered effectively, pointing out that Ryan had voted to cut funds for embassy defenses.

As the debate unfolded, Biden repeatedly showed greater understanding and depth on foreign policy. It wasn’t that Ryan was bad; Biden was consistently better, although his frustration with Ryan’s shallowness sometimes got the better of him, with his smiles and grimaces. On domestic policy, Biden scored points and raised questions about Mitt Romney that Obama did not on tax equity, deficit reduction and Medicare. Ryan had a nice comeback on the 47 percent, reminding Biden that he doesn’t always state things well, either. But Biden pushed through the laughter and spoke passionately about Romney’s callousness toward the middle class.

Since the performance of the moderator seems to be relevant, Martha Raddatz did a good job. She blended topicality, follow-ups and reflective questions.

I doubt this Biden victory will make a lasting difference in the race’s trajectory. But a Biden “loss” certainly would have.

Next stop: Hofstra.