Having already internalized the fact that Romney and Ryan routinely lie about their fiscal proposals, I haven’t paid very close attention to the sleuthing efforts of various analysts to prove that their latest assertions about being able to massively cut high-end tax rates while somehow balancing the budget and avoiding any middle-class tax increases is a lie, too.

But Kevin Drum (with an assist from Catherine Rampell) nails the latest Romney/Ryan mendacity so succinctly that it’s worth a shout-out:

[E]ven if you completely eliminated all tax deductions for high earners — the mortgage interest deduction, the charitable deduction, the exclusion of healthcare benefits, etc. — it still wouldn’t make up for the 20% rate cut Romney wants to give them. Their total tax bill would go down. However, Romney has also said that his total tax plan is revenue neutral, which means that someone else’s tax bill has to go up to make up for the tax cuts he’s giving to the rich. But Romney says that won’t happen either. Middle-class taxes, on net, will stay the same. In other words:

-$251 + $165 + 0 = 0

In my 7th-grade pre-algebra class, this bit of arithmetic wouldn’t have passed muster. Maybe they taught math differently at Cranbrook. In any case, all I’d really like to see from Romney is a proof of concept. It doesn’t have to be his final plan or anything like that. Just any combination of a 20% rate cut and the closing of tax deductions that produces no net tax decrease for the rich. Anything at all that proves it can be done.

Kevin goes on to predict that if cornered on their fiscal math, Romney and Ryan will retreat to the supply-side “dynamic scoring fairy,” pretending it will all come out in the wash once their tax cuts have made America a job-creating paradise where revenues pour into the Treasury from matchless growth. That’s probably true, though we shouldn’t discount the high probability that R&R will just brazen it through and not bother to square the circle.

Ed Kilgore

Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.