Almost all federal taxpayers who itemize their charitable deductions on their returns deduct the full amount, in order to keep their tax burden as low as possible. Mitt Romney didn’t do that in 2011, according to tax returns released today, leaving $1.8 million un-deducted so he could tell voters he paid a federal tax rate of at least 13 percent. That’s a luxury reserved only for wealthy politicians who can afford to pay an extra few hundred thousand for image purposes.

But one unfortunate line on a memo from Mr. Romney’s lawyer, accompanying the tax returns, suggests that Mr. Romney really doesn’t see much difference between giving to charity and giving to the government.

“Over the entire 20-year period, the total federal and state taxes owed plus the total charitable donations deducted represented 38.49% of total AGI,” the memo said, referring to Mr. Romney’s adjusted gross income. In his mind, apparently, you can just add up the two figures into a new hybrid column, perhaps called, Total Obligation to Society, and make yourself look even more generous.

It doesn’t work that way, however; charity and taxes cannot be conflated to make it sound like you are “giving away” a larger portion of your income than you are. Conservatives can hate paying taxes, and Mr. Romney in particular appears to hate having tax money spent on the “dependent class,” but that doesn’t make the government a charity.

Taxes represent the obligations citizens have to each other and to society, fostering physical safety with defense and law enforcement spending, economic safety with public works, and personal welfare for the needy. Charity is entirely voluntary, even for those who, like Mr. Romney, are asked by their religious authorities to tithe a fixed portion of their income. Those donations play a vital role in every American community, but they can never take the place of a firm government safety net, as much as they are preferred by the right to taxes.

One would think that someone running to be the government’s chief executive would be proud to make tax payments, and would not try to reduce them through exotic foreign tax shelters and an outsized IRA, as Mr. Romney has done for years. But the announcement today that he had deliberately “overpaid” his taxes was grudging and entirely for show. He overpaid them only so that he couldn’t be accused of paying far less before the election.

Despite his accountant’s statement today that he had never paid less than 13.66 percent of his income in taxes over the last 20 years (a level that would make many middle-class taxpayers jealous), it is still an assertion that has not been backed up by the release of actual tax returns for that period. For all the highly trumpeted discretionary donations he has made, Mr. Romney apparently still doesn’t want the public to see how assiduously he has worked to lower his most important social obligation.