FactCheck.org and Politifact are both suggesting that Dems at the convention last night misled viewers about Mitt Romney’s tax plan. Multiple Dem speakers argued that his plan would raise taxes on the middle class while cutting them for the rich.

FactCheck.org says this is problematic because Romney has “promised” not to raise them on the middle class; Politifact roughly agrees.

This is a bit silly. As Steve Benen and Travis Waldron note, what matters here is that Romney’s plan promises across the board tax cuts and it promises to remain revenue neutral. The Tax Policy Center has found that if both promises are kept, Romney’s plan must pay for itself by increasing the middle class’ tax burden.

That said, the fact checkers are right in their narrow claim that the current Dem formulations are somewhat misleading, and this illustrates a problem with Dem messaging.

Here’s how Dem Governor Martin O’Malley put it yesterday: “Romney says he will cut taxes for millionaires and raise them for the middle class.” An Obama ad says: “Under the Romney plan, a middle-class family will pay an average of up to $2,000 more a year in taxes.”

The trouble with this message is that it risks confusing viewers and could make it easier for Romney to confuse the issue further. Here’s why: The Dem messaging sounds like an objective statement of what’s in the Romney tax plan — that is, it could be heard by voters as a declaration of Romney’s explicitly stated intentions, as if Romney has proposed to raise middle class taxes. When Romney says, “they’re lying — that’s not what I’ve proposed,” voters may throw up their hands and decide they don’t know who to believe.

What is required is a message that more clearly states what Romney is actually claiming — and why it’s complete nonsense. Dems need to say: You will hear Romney promising to cut your taxes and get our fiscal house in order. But guess what — he won’t tell you how he will pay for all that — which inevitably means you will pick up the tab. Seen this movie before?

Yes, that sounds more complicated, and perhaps it’s not great in a 30-second ad, but it may be worth it. If voters are told this, they will understand what’s happening when they hear Romney promising them that he will cut their taxes. Now they risk concluding that they can’t ever know who’s leveling with them.

Dems should lead voters through Romney’s absurd promises to a clearer understanding of the gaping holes in them. Such directness with voters could also enhance a larger dynamic in which the GOP ticket is the one getting overwhelmingly tagged by the national media for its serial mendacity and finding its integrity called into question.