"The constitutional propriety of Congress's decision to decline to extend federal benefits immediately to newly recognized types of marriages is bolstered by Congress's articulated interest in preserving the scarce resources of both the federal and State governments. DOMA ensures that evolving understandings of the institution of marriage at the State level do not place greater financial and administrative obligations on federal and state benefits programs. Preserving scarce government resources — and deciding to extend benefits incrementally — are well-recognized legitimate interests under rational-basis review. See Butler, 144 F.3d at 625 ("There is nothing irrational about Congress's stated goal of conserving social security resources, and Congress can incrementally pursue that goal."); Hassan v. Wright, 45 F.3d 1063, 1069 (7th Cir. 1995) ("[P]rotecting the fisc provides a rational basis for Congress' line drawing in this instance."). Congress expressly relied on these interests in enacting DOMA: Government currently provides an array of material and other benefits to married couples in an effort to promote, protect, and prefer the institution of marriage. . . . If [a State] were to permit homosexuals to marry, these marital benefits would, absent some legislative response, presumably have to be made available to homosexual couples and surviving spouses of homosexual marriages on the same terms as they are now available to opposite-sex married couples and spouses. To deny federal recognition to same-sex marriages will thus preserve scarce government resources, surely a legitimate government purpose."
This is from the US Justice Department's filing in a challenge to the Defense of Marriage Act in California. This paragraph effectively says that it's okay for me to be taxed on Ruth's health benefits when my straight married co-workers spouses' benefits are tax-exempt--because there's only so much money, and the government has to preserve resources. If I die, Ruth doesn't get my Social Security benefits, and oh well, I guess that's the Gay Tax.
I distinctly remember Obama promising to work to repeal DOMA during the campaign. Yeah, only not so much.