The Tax Policy Center, analyzing that proposal, found that it would close only $1.3 trillion of Mr. Romney’s newly dug revenue hole. And no matter how many times the Romney campaign insists that independent studies “have demonstrated the Romney plan works,” that simply isn’t true — not with the parameters (revenue neutrality and no tax increases for those making less than $200,000) that Mr. Romney has set, and not unless you assume economic growth far greater than that predicted by Mr. Romney’s own advisers.