1st Circuit says Defense of Marriage Act is unconstitutional.

"The appeals court agreed with a lower court judge who ruled in 2010 that the law is unconstitutional because it interferes with the right of a state to define marriage and denies married gay couples federal benefits given to heterosexual married couples, including the ability to file joint tax returns."

The court didn't rule on [whether] states without same-sex marriage cannot be forced to recognize gay unions performed in states where it's legal. It also wasn't asked to address whether gay couples have a constitutional right to marry.

ADDED: Here is the opinion. After concluding that the equal protection doctrine requires minimum scrutiny (but not "the extreme deference accorded to ordinary economic legislation"), the court switches to discussing federalism. Congress uses the concept of marriage in many federal programs involving taxing and spending, and it normally relies on the states' determinations of who is married, but — the court says — that doesn't mean Congress is required to do so.

The court looks at the 10th Amendment but distinguishes this case from Printz and New York v. United States, which involved Congress commandeering the internal operations of state or local government. And the court looks at the Spending Clause doctrine and finds no limitation, because Congress is merely defining the terms of various spending programs.

However, the denial of federal benefits to same-sex couples lawfully married does burden the choice of states like Massachusetts to regulate the rules and incidents of marriage; notably, the Commonwealth stands both to assume new administrative burdens and to lose funding for Medicaid or veterans' cemeteries solely on account of its same-sex marriage laws. These consequences do not violate the Tenth Amendment or Spending Clause, but Congress' effort to put a thumb on the scales and influence a state's decision as to how to shape its own marriage laws does bear on how the justifications are assessed.

That's quite a sentence! There's no violation of the 10th Amendment or the Spending Clause, but because federal choices affect how states may decide to exercise their powers, the court will give congressional decisions less deference.

In United States v. Morrison, 529 U.S. 598 (2000), and United States v. Lopez, 514 U.S. 549 (1995), the Supreme Court scrutinized with special care federal statutes intruding on matters customarily within state control. The lack of adequate and persuasive findings led the Court in both cases to invalidate the statutes under the Commerce Clause even though nothing more than rational basis review is normally afforded in such cases.

The Supreme Court has made somewhat similar statements about the need for scrutiny when examining federal statutes intruding on regulation of state election processes. Nw. Austin Mun. Util. Dist. No. One v. Holder, 129 S. Ct. 2504, 2511 (2009); cf. City of Boerne v. Flores, 521 U.S. 507, 534 (1997) (calling RFRA a "considerable congressional intrusion into the States' traditional prerogatives and general authority to regulate for the health and welfare of their citizens").

True, these federalism cases examined the reach of federal power under the Commerce Clause and other sources of constitutional authority not invoked here; but a statute that violates equal protection is likewise beyond the power of Congress. See Moreno, 413 U.S. at 541 (Douglas, J., concurring). Given that DOMA intrudes broadly into an area of traditional state regulation, a closer examination of the justifications that would prevent DOMA from violating equal protection (and thus from exceeding federal authority) is uniquely reinforced by federalism concerns.

This is a remarkable move! The enumerated powers cases involve judicial line-drawing about what matters may be governed by federal law and what are left exclusively to the states. The cases about rights concern what is left to individual citizens. It's one thing to say that federalism concerns affect what is governed by federal law and what is left exclusively to the states, quite another to say that the realm that belongs to the individual increases or decreases based on federalism concerns. Our rights are bigger when states have interests and smaller when they don't? The court seems to be creating a hybrid of rights and state interests.

Or we might understand this as an idea about deference to Congress: The question isn't so much whether Congress has power or not, but whether the court will see the lack of power. What the court is doing is looking at all the factors that affect how closely it ought to look at what Congress has done. Although as a matter of doctrine, the official level of scrutiny is minimum — Congress need only have a legitimate interest that's rationally related to the policy it has adopted — the fact that this isn't just economic legislation makes the court look a little more closely and, separately, so does the fact that the states are burdened in an area they have traditionally controlled.

With the degree of scrutiny established, the court goes on to the interests that supposedly support DOMA. One is "preserving scarce government resources."

But, where the distinction is drawn against a historically disadvantaged group and has no other basis, Supreme Court precedent marks this as a reason undermining rather than bolstering the distinction. Plyler v. Doe, 457 U.S. 202, 227 (1982); Romer, 517 U.S. at 635. The reason, derived from equal protection analysis, is that such a group has historically been less able to protect itself through the political process. Plyler, 457 U.S. at 218 n.14; United States v. Carolene Prods. Co., 304 U.S. 144, 152 n.4 (1938).

Another purported interest is "to support child-rearing in the context of stable marriage," but the court finds "a lack of any demonstrated connection between DOMA's treatment of same-sex couples and its asserted goal of strengthening the bonds and benefits to society of heterosexual marriage."

A third interest is "moral disapproval of homosexuality":

But, speaking directly of same-sex preferences, Lawrence ruled that moral disapproval alone cannot justify legislation discriminating on this basis. 539 U.S. at 577-78. Moral judgments can hardly be avoided in legislation, but Lawrence and Romer have undercut this basis. Cf. Palmore v. Sidoti, 466 U.S. 429, 433 (1984).

Lastly, it was argued that Congress, facing a period of changing state laws, had an interest in "freezing" the law in place, taking "a temporary time-out." But, the court says, DOMA isn't framed as a temporary measure.

If we are right in thinking that disparate impact on minority interests and federalism concerns both require somewhat more in this case than almost automatic deference to Congress' will, this statute fails that test.

Invalidating a federal statute is an unwelcome responsibility for federal judges; the elected Congress speaks for the entire nation, its judgment and good faith being entitled to utmost respect.... 

But what about deference to tradition — the tradition of marriage as the union of one man and one woman? Why can't Congress base its law on that?

Traditions are the glue that holds society together, and many of our own traditions rest largely on belief and familiarity--not on benefits firmly provable in court. The desire to retain them is strong and can be honestly held.

For 150 years, this desire to maintain tradition would alone have been justification enough for almost any statute. This judicial deference has a distinguished lineage, including such figures as Justice Holmes, the second Justice Harlan, and Judges Learned Hand and Henry Friendly. But Supreme Court decisions in the last fifty years call for closer scrutiny of government action touching upon minority group interests and of federal action in areas of traditional state concern.

To conclude, many Americans believe that marriage is the union of a man and a woman, and most Americans live in states where that is the law today. One virtue of federalism is that it permits this diversity of governance based on local choice, but this applies as well to the states that have chosen to legalize same-sex marriage. Under current Supreme Court authority, Congress' denial of federal benefits to same-sex couples lawfully married in Massachusetts has not been adequately supported by any permissible federal interest.