In the wake of the Democratic convention, the Republican candidate again promised to “cut the deficit and get us back on track to a balanced budget.” He even hinted that his own party bears some responsibility for ballooning federal deficits and debt. “We’re going to finally have to do something that Republicans have spoken about for a long time and for a while we didn’t do it. When we had the lead, we let people down,” he said the other day, presumably referring to the last Republican president, whose name must never be mentioned, and the Congressional leadership during that administration.

And “for a while” presumably refers to the past 30 years or so.

Romney also says that he watched none of the speeches at the Democratic convention. He obviously missed the one that might have helped him figure out exactly what his party has been doing wrong. “I hear Bill Clinton spoke for like, 50 minutes?” he snarked at a public appearance on Friday. Yes, the former president spoke for just over 49 minutes – and he articulated a message that could enlighten Romney. Clinton’s lesson might be titled “Arithmetic for Billionaires.”...

...as Clinton noted, they propose still another round of tax cuts for the wealthiest households – including their own and those of their most generous supporters – that would cost the Treasury at least $5 trillion. And they insist on increasing the defense budget by hundreds of billions, too.

What Clinton asked is how the Republican nominees propose to pay for those lavish favors to themselves and their friends. Doing the arithmetic himself, he came up with three possible answers: They will raise taxes on the middle class by taking away mortgage, charitable and other deductions, so that billionaires can have another tax break. They will cut federal spending so deeply that infrastructure, education, science, technology, and health care will be ruined for the future. Or they will do nothing, and explode the debt, just as their predecessors have done repeatedly over the past three decades.