Massachusetts Attorney General Martha Coakley is suing the Federal Government on behalf of the state of Massachusetts, claiming that the Federal Defense of Marriage Act “interferes with the Commonwealth’s sovereign authority to define and regulate marriage”. A portion of the suit alleges that the Federal Government has exceeded the limitations on its power set by the Tenth Amendment of the United States Constitution…

81. The Tenth Amendment to the United States Constitution expressly reserves to the states all powers except those limited powers granted to the federal government.
82. The Tenth Amendment ensures the division of powers between the states and federal government that is necessary for the dual sovereignty of the federal system.
83. The Tenth Amendment preserves for the states the authority to regulate and define marriage for their citizens.
84. Congress lacks the authority under Article I of the United States Constitution to regulate the field of domestic relations, including marriage.
85. Section 3 of DOMA violates the Tenth Amendment, exceeds Congress’s Article I powers, and runs afoul of the Constitution’s principles of federalism by creating an extensive federal regulatory scheme that interferes with and undermines the Commonwealth’s sovereign authority to define marriage and to regulate the marital status of its citizens.
86. Enforcement of Section 3 of DOMA unconstitutionally commandeers the Commonwealth and its employees as agents of the federal government’s regulatory scheme and requires the Commonwealth to facilitate the implementation of a discriminatory federal policy.

The suit stakes out the position that Congress doesn’t have the right to establish a definition of marriage, even for Federal law, because establishing a definition of marriage is reserved to the states.
Though I oppose legalizing same-sex marriage (just like President Barack Obama and Vice-President Joseph Biden do), given that the power to define marriage is certainly not delegated to the Federal government anywhere in the Constitution, if some kind of reasonable alignment between written law and rationality still exists in the world of self-governance, then it is difficult to see where the definition of marriage isn’t something that is outside of the power of the Federal Government to decide, if the Tenth Amendment has any meaning at all.
But I also wonder if progressives and other cultural liberals who support Attorney General Coakley’s action will be able to identify other areas where the reach of the Federal government needs to be scaled back to be brought into line with the Tenth Amendment, or if their sudden discovery of its importance will be applied only to same-sex marriage, as a case of activists arguing principles they doesn’t really believe in, in order to get the policy outcome they want.
In case you’ve forgotten, the Tenth Amendment reads…

The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.

(Note: Readers from Bristol, RI may want to check with town authorities, to determine if reading the above excerpt complies with all local regulations).