Same-sex partners cannot claim the privileges and benefits that Congress makes available to those who are married or widowed. For example, they cannot file joint income tax returns, receive Social Security benefits on their partner's wages, collect life insurance following the death of a military service member or obtain a green card for a partner from another country.

The anti-DOMA lawsuit claims it is unfair and discriminatory that same-sex couples who, they say, are legally married under state law are not recognized as such by the U.S. government. But the federal government must consider the entire nation, including the 43 states whose laws categorically declare that same-sex marriages from other states are not valid and may not be recognized for any purpose whatsoever.

If we didn't have a uniform federal definition of marriage, it wouldn't be long before every state had same-sex couples saying they were "married" in Massachusetts, Vermont or Iowa, and demanding that their "marriages" be recognized by those 1,138 federal laws even after moving to a traditional marriage state.

If judges overrule Congress and the majority of the American people by striking down DOMA, it would be the same type of judicial supremacy that occurred 152 years ago in the famous Dred Scott case. The U.S. Supreme Court ruled that once a slave became "property" under the laws of a slave state, that legal status had to be maintained and respected even after the slave was taken to a free state, or even to a U.S. territory where slavery was specifically forbidden by Congress.

In his first campaign for the Illinois state Senate in 1996, Barack Obama wrote: "I favor legalizing same-sex marriages, and would fight efforts to prohibit such marriages." On his first day as president, the White House Website was updated to declare: "Obama also believes we need to repeal the Defense of Marriage Act and enact legislation that would ensure that the 1,100-plus federal legal rights and benefits currently provided on the basis of marital status are extended to same-sex couples in civil unions and other legally recognized unions."

Will the Obama Justice Department do its duty and defend federal law? Seventy-seven members of Congress wrote to Attorney General Eric Holder on March 24 requesting assurances by April 1 "that you plan to defend vigorously this law in its entirety."

We're still waiting for Holder's response. Americans must preserve DOMA at any cost.