Attention deficit hawks!
The CBO’s findings suggest that federally recognized gay marriage would reduce the budget deficit by about $450 million a year, or roughly 0.01 percent of total federal spending…
Most people will think of it as changing income taxes and benefits for gay public employees. But some of the biggest effects come in welfare programs: Marriage makes people more robust against financial shocks and less likely to qualify for welfare programs. Same-sex marriage would save hundreds of millions of dollars a year by getting some gay men and lesbians off the Medicaid and Supplemental Security Income rolls.
On the revenue side, the CBO estimated that gay marriage in all 50 states would increase tax receipts by about $400 million a year if the George W. Bush tax cuts were extended and by about $700 million a year if they were not. Because those tax cuts ended up being mostly extended, the answer is probably somewhere in the middle, but closer to $400 million.
The added revenue comes from the “marriage penalty”: Two-earner married couples where each spouse has a similar income tend to be taxed more heavily than they would be if both partners were single. Other couples get a “marriage bonus,” generally when the spouses’ incomes are very unequal, but the marriage penalty effect is more important.