Richard Milhous Nixon said in 1968 that the war in Vietnam was the critical concern of that year’s presidential contest, the one issue that had to be addressed by the candidates. And he addressed it with a “secret plan” to end the war. No details during the campaign, the Republican nominee for president explained; voters just needed to trust him and he would cut the right deals once elected.

Paul Ryan says in 2012 that budgeting to cut taxes for the rich while at the same time doing away with deficits is the critical issue of the presidential contest, the one that has to be addressed by the candidates. And he addresses the issue with a secret plan to cut taxes and balance budgets. No details during the campaign, the Republican nominee for vice president explains; voters just need to trust him and he will cut the right deals once elected.

In the most remarkable exchange of the only vice presidential debate of 2012 came when moderator Martha Raddatz said to Ryan: “You have refused…to offer specifics on how you pay for that 20 percent across-the-board tax cut. Do you actually have the specifics? Or are you still working on it, and that’s why you won’t tell voters?

That’s where Ryan borrowed a political page from “Tricky Dick”:

RYAN: Different than this administration, we actually want to have big bipartisan agreements. You see, I understand the…

RADDATZ: Do you have the specifics? Do you have the… Do you know exactly what you’re doing?

RYAN: Look—look at what Mitt Romney—look at what Ronald Reagan and Tip O’Neill did. They worked together out of a framework to lower tax rates and broaden the base, and they worked together to fix that.

What we’re saying is, here’s our framework. Lower tax rates 20 percent. We raised about $1.2 trillion through income taxes. We forego about $1.1 trillion in loopholes and deductions. And so what we’re saying is, deny those loopholes and deductions to higher-income taxpayers so that more of their income is taxed, which has a broader base of taxation so we can lower tax rates across the board. Now, here’s why I’m saying this. What we’re saying is, here’s the framework…

We want to work with Congress—we want to work with the Congress on how best to achieve this. That means successful. Look…

RADDATZ: No specifics, again.

RYAN: Mitt—what we’re saying is, lower tax rates 20 percent, start with the wealthy, work with Congress to do it…

RADDATZ: And you guarantee this math will add up?

RYAN: Absolutely.

That was it. No specifics. No plan. Just a plea for voters to trust Mitt Romney and Paul Ryan to “fill in the details.”

Vice President Biden, who was already well aware that he was winning the debate he had to win after last week’s presidential debate debacle, pounced. Displaying the skills that would lead 50 percent of undecided voters to tell pollsters that Biden won the debate, while only 31 percent picked Ryan, the experienced vice president hit the inept pretender with the obligatory “I was there when Ronald Reagan tax breaks—he gave specifics” line.

Then the vice president explained why Ryan was avoiding specifics. Under even the most basic outlines of the Romney-Ryan plan “ taxes go up on the middle class, the only way you can find $5 trillion in loopholes is cut the mortgage deduction for middle-class people, cut the healthcare deduction, middle-class people, take away their ability to get a tax break to send their kids to college. That’s why they arrive at it.”

Zing.

Easily the most substantive “zing” of the night. But not the most amusing “zing.” That came after Ryan condemned the 2009 stimulus bill as “Crony capitalism and corporate welfare.”

It went like this:

BIDEN: I love my friend here. I—I’m not allowed to show letters but go on our website, he sent me two letters saying, ‘By the way, can you send me some stimulus money for companies here in the state of Wisconsin?” We sent millions of dollars…

RADDATZ: You did ask for stimulus money, correct?

RYAN: On two occasions we—we—we advocated for constituents who were applying for grants. That’s what we do. We do that for all constituents who are…

BIDEN: I love that. I love that. This was such a bad program and he writes me a letter saying—writes the Department of Energy a letter saying, ‘The reason we need this stimulus, it will create growth and jobs.’ His words.”

Ryan’s Nixonian turns gave Biden the upper hand on a night when Democrats needed a win.

By the time the debate turned to the issues on which Biden was always going to have the upper hand: defending Social Security, Medicare and Medicaid, all the vice president really had to say was: “Who you believe, the AMA, me, a guy who’s fought his whole life for this, or somebody who would actually put in motion a plan that knowingly cut—added $6,400 a year more to the cost of Medicare?”

All he had to say with regard to wild claims about how Obamacare threatens seniors was: “You know, I heard that death panel argument from Sarah Palin. It seems every vice presidential debate I hear this kind of stuff about panels.”

And all he really had to say, after Ryan took the most radical anti-choice stance ever uttered on a debate stage by a major-party nominee, was that, while he respects the teachings of his Catholic religion: “I do not believe that we have a right to tell other people that, women, that they can’t control their body.… I’m not going to interfere with that.”

It may not be entirely fair to compare Ryan with Nixon. In truth, the former president would never have bumbled Thursday night’s Afghanistan questions as badly as did this year’s Republican vice presidential nominee—who was reduced to repeated the seasons of the year “winter, spring, summer fall” in an attempt to cover for his misstatement of details of the current fight.

But Ryan played Nixon Thursday night.

On issue after issue, the Republican vice presidential candidate danced around the details.

But unlike last week when Barack Obama allowed Mitt Romney to repurpose himself as a credible contender, Joe Biden was having none of it.

Hubert Humphrey never got a chance to call Richard Nixon out on a debate stage in 1968.

If he had, that very close election might have finished differently.

But in the end, it was not Biden who made Ryan the Nixon of the night.

It was Ryan.

On what he says is the most important issue of the campaign, the “fiscal cliff” issue that brought him to national attention and a place on the GOP ticket, Ryan had no details, no specifics, just a “secret plan.”

For more post-debate rundowns, check out Greg Mitchell on who won last night’s VP faceoff.

Want more Election 2012 coverage from The Nation? Sign up for our weekly Election 2012 email here.