You can't hit what you can't see. That in a nutshell has been Mitt Romney's campaign strategy for months. From his mysterious tax returns and erased Massachusetts records to his shifting immigration stands, AWOL strategy for Afghanistan and so much more, Team Mitt long ago decided that discretion was the better part of valor. But on his magical tax plan more than any other issue, Mitt Romney has insisted that you can't criticize what he refuses to reveal.

Voters should have seen this coming. Back in March, Romney himself gave the game away. As he explained the shell game to CNBC, how he would offset an estimated $5 trillion in lost revenue over the next decade would remain a mystery, at least until after the election:

"So I haven't laid out all of the details about how we're going to deal with each deduction, so I think it's kind of interesting for the groups to try and score it, because frankly it can't be scored, because those kinds of details will have to be worked out with Congress, and we have a wide array of options."

Romney may have an array of options, but none of them can be discussed publicly simply because his math doesn't work and his promises cannot be kept. He has pledged to deliver a 20 percent across-the-board income tax cut, one which is revenue neutral, does "not place a larger share of the tax burden on middle-income taxpayers" and "make[s] sure the top 1 percent is paying their current share or more." And far from allowing President Romney to "cut, cap and balance" the budget, his plan will explode the national debt. Unless, of course, Romney comes clean on which of $1 trillion in tax credits, deductions, and loopholes he would curtail. And that, his economic adviser Glenn Hubbard made clear in February, won't be happening:

"It is not his intention to take on any specific deduction or exclusion and eliminate it."

It was that "if you show me yours I won't show you mine" approach that let Mitt Romney float like a butterfly and sting like a bee during last week's presidential debate. Early on, Obama rightly noted that Romney's proposals require slashing $5 trillion from the U.S. Treasury and boosting defense spending by $2 trillion more, all while remaining silent on which deductions and loopholes he would close the pay for it. In response, the Republican lectured the President for critiquing the mystery meat that is the Romney tax plan:

"First of all, I don't have a $5 trillion tax cut. I don't have a tax cut of a scale that you're talking about. My view is that we ought to provide tax relief to people in the middle class. But I'm not going to reduce the share of taxes paid by high-income people...
So if the tax plan he described were a tax plan I was asked to support, I'd say absolutely not. I'm not looking for a $5 trillion tax cut. What I've said is I won't put in place a tax cut that adds to the deficit. That's part one. So there's no economist that can say Mitt Romney's tax plan adds $5 trillion if I say I will not add to the deficit with my tax plan.
Number two, I will not reduce the share paid by high-income individuals...And number three, I will not under any circumstances raise taxes on middle-income families. I will lower taxes on middle-income families."

Just to be on the safe side, Romney on the eve of the debate further muddied the waters by floating a new, ill-defined tax proposal to cap the total dollar value of individual deductions. Depending on how Romney's cap is constructed, it could potentially raise a lot of tax revenue while putting most of the burden on upper-income Americans. But thus far, Romney has refused to commit to a dollar figure (he's mentioned $17,000 and even said "make up a number, $25,000, $50,000"), let alone set in stone whether all tax credits and deductions are covered by his new gambit. And as GOP Florida recount attorney turned Romney adviser Benjamin Ginsberg pointed out last week, voters will just have to stay tuned for details:

"You pay for the tax cuts in the way that Governor Romney is going to articulate in the next five weeks. You are going to hear that from his mouth in the coming days."

Or maybe not. On Sunday, GOP strategist Michael Murphy (who as an adviser to Massachusetts Governor Romney in 2005 admitted Mitt's "been a pro-life Mormon faking it as a pro-choice friendly") defended the Republican nominee's continued secrecy:

"Here is the problem. You guys won't give him any credit for closing loopholes, because like you guys, he won't name the loopholes. Why? Because you'll attack him for doing it. You attack him for not giving you a little target... and then you attack him when you get the target."

And Mitt Romney won't be giving voters any details--or President Obama any target--any time soon. As he told the Weekly Standard earlier this year, the lesson he learned from his 1994 defeat at the hands of Ted Kennedy was "I'm not going to give you a list right now." In December, the reliably Republican Wall Street Journal concluded as much:

Amid such generalities, it's hard not to conclude that the candidate is trying to avoid offering any details that might become a political target. And he all but admits as much. "I happen to also recognize," he says, "that if you go out with a tax proposal which conforms to your philosophy but it hasn't been thoroughly analyzed, vetted, put through models and calculated in detail, that you're gonna get hit by the demagogues in the general election."

Of course, what Mitt Romney labels "demagogues," most Americans call "voters." And as conservative columnist George Will put it, when Romney speaks to them he lacks "the courage of his absence of convictions." Sadly, when it comes to his campaign strategy of cowardice, the electorate might just let him get away with it.