On "Fox News Sunday," Chris Wallace repeatedly asked Paul Ryan to explain how the math on his tax plan added up. Ryan pretended not to understand Wallace's question, called the Tax Policy Center study "thoroughly debunked" when it's not even been dented, and, finally, retreated behind a particularly sad excuse for a politician who built his reputation on explaining policy in understandable terms: “It would take me too long to go through all the math.”

Aside from betraying the principles of policy communication that Ryan once stood for, this response isn't even true. It doesn't take very long at all to go through the math. In fact, it's only a few steps.

1) In 2015, the Romney-Ryan rate reduction will reduce tax revenue by $480 billion compared to current policy. That's the raw number, before you start arguing over behavioral responses or growth.

2) Of that $480 billion, 39.1 percent, or $187 billion, will go to the top 1 percent.

3) Since the Romney-Ryan plan isn't supposed to cut taxes on the rich or increase the deficit, all Romney and Ryan need to do is identify $480 billion in tax breaks they're going to close, of which at least $187 billion needs to come from the top 1 percent.

4) If they believe that accelerated economic growth or behavioral responses are going to close some of that gap for them, they need to say how much, and what they're basing that assumption on.

That's it. This isn't advanced calculus. It's arithmetic.

Things can get more complicated when you get into interaction effects between different tax breaks and microbehavioral responses, but that doesn't need to be done on television, or even by the Romney campaign. They could just send a list of tax breaks they'll close over to a nonpartisan group such as the Tax Policy Center, let the TPC run the breaks through their tax model (which takes all these effects into account automatically) and, if the TPC certifies the plan as workable, release the list of breaks publicly alongside the TPC's seal of approval. I promise them that the moment they do that, this controversy will end.

And, of course, if they were worried that "Fox News Sunday" wouldn't give them the time necessary to explain the math, they could publish a detailed explanation on their Web site, or Ryan could record a three-hour YouTube video walking viewers through the numbers. 

But they're not going to do that, because the problem isn't that the math on their plan takes too long to detail. It's that the math on their plan can't be done. Or, it can be done, but when you do it, you get answers the Romney campaign doesn't like — for instance, that the tax plan will either raise taxes on the middle class or add to the deficit.

Whenever they brush against the specifics of it, that becomes very clear, very quickly. And so Ryan pretends that the policy is too complicated for the country to understand, when in fact it's too flawed for him to explain.