[If he had claimed the full $4 million, it] would have conflicted with his statement in August that he has paid at least 13 percent the past ten years. So Romney opted to limit his charitable deduction to just $2.25 million, essentially agreeing to pay the government more in taxes than he needed to. In the end, Romney had an effective federal tax rate of 14.1 percent.
There’s nothing wrong with voluntarily donating a bit more to reduce the federal deficit. Although there is this awkward quote from Romney during a primary debate in January: “I pay all the taxes that are legally required and not a dollar more,” he said. “I don’t think you want someone as the candidate for president who pays more taxes than he owes.”