A study by the Congressional Budget Office (CBO) concludes that same-sex marriage would be a windfall for the federal budget, reports the Gay Financial Network (and here's a direct link to the CBO study).
The CBO finds that letting same-sex couples marry would save the government a cool $1 billion per year by boosting income tax revenue and lowering spending on Medicaid and Supplemental Security Income.
But don't expect that argument to sway social conservatives.
They see themselves engaged in a pitched moral battle and would
spend the country into bankruptcy to prevent state recognition
(and, as they see it, sanctification) of same-sex unions.