Ask a political consultant, and she'll tell you that if you're a candidate running for something like the House, there's no point in putting out position papers. Sure, you want to let people know you're substantive and have thought seriously about policy, but putting it down on paper only brings you grief. Nobody will be convinced to vote for you because of something in a position paper, but people may well find therein a reason to vote against you. And your opponent will go through it and find things to take out of context and attack you with.
Presidential campaigns, however, are supposed to be different. A new congressman can coast through a term without anything much resembling an agenda, but a president is supposed to have a whole slate of policies he wants to implement. So presidential campaigns employ people whose job it is to devise and refine plans that can be put into practice in the White House. But now, Mitt Romney and the people who work for him, are coming out and saying more explicitly than presidential candidates are supposed to that there's just not much point in telling people in any detail what the man who would be president wants to do: "'What you're going to see is a campaign that has clear direction, but not a Simpson-Bowles or Ryan-budget level of detail,' the Romney adviser said. 'It's not only politically unwise to do that, but it’s not how the voters engage in a presidential campaign.'" Both Romney and Paul Ryan are saying the same thing themselves. He says he'll close tax loopholes, but which ones? You know, loopholes--we'll figure it out later. He says he wants huge budget cuts, but where will the cuts come from? Oh, different programs. There's no point in saying now, because the Democrats will just go after us. You'll recall that both Mitt and Ann Romney have offered similar justifications for not releasing their tax returns beyond the one year they've already released: "The more we release," Ann Romney said, "the more we get attacked, the more we get questions, the more we get pushed. We have done what's legally required, and there's going to be no more tax releases given."
Now here's the thing. If there was nothing untoward in the tax returns, you might presume that although Democrats would try to take something out of context and make a big deal about it, they'd fail. After all, Romney would have the truth on his side, and it isn't like he doesn't have a megaphone with which he can argue back at whatever his opponents claim. You can say the same thing about policy: Yes, Democrats won't give Mitt Romney's preferred reading to the things he wants to do, but if his plans really are superior, a vigorous debate should let the truth rise above the lies.
But when it comes to arguments based on things taken out of context and willful distortions of the facts, Mitt Romney knows whereof he speaks. For a couple years now he's been taking something Barack Obama said out of context and twisting it to claim that Obama doesn't believe America is anything special. He recently took out of context half a sentence Obama said ("You didn't build that") and made it the very centerpiece of his campaign. Now his campaign is devoting its ample resources of time and money to convincing people to believe a spectacularly dishonest reading of an Obama administration policy on welfare. Taking things out of context is to the Romney campaign what oil changes are to Jiffy Lube. They may do a couple of other things on the side, but that's their main business.
You can say that Mitt owes us more details about who he is and what he wants to do. But when he says he's afraid that the details will be taken out of context and distorted, he's speaking from experience.