As the U.S. Supreme Court considers two cases dealing with same-sex marriage, the Religious Right and its allies are attempting to sway the justices with a barrage of briefs in support of the Defense of Marriage Act (DOMA) and California’s Proposition 8.

Most of these groups are tossing around some pretty flimsy secular arguments in a weak attempt to make it seem like their opposition isn’t based in religious dogma. We know better.

Consider this breakdown from USA Today, which shows the various arguments from religious lobbies that want their sectarian doctrines to be enforced by the civil marriage laws of the United States. The article notes that one of the most quoted sources among these many legal briefs is none other than the Bible.

Still, some tried to pretend that they support DOMA and Prop 8 for secular reasons.

Take the U.S. Conference of Catholic Bishops. The bishops said that if gay marriage is legal, they would be forced to accept it in order to remain tax exempt and be eligible for government contracts.

“If the Constitution were construed to require government affirmation of same-sex relationships as marriage, it would seem a short step to requiring such affirmation as a condition of receiving government contracts, participating in public programs or being eligible for tax exemption,” the bishops said. “Those who disagree with the government's moral assessment of such relationships would find themselves increasingly marginalized and denied equal participation in American public life and benefits.”

That seems highly unlikely. The bishops are already known to discriminate and ignore the provisions outlined in government contracts if they contradict their beliefs, and yet Catholic organizations remain tax exempt and Catholic groups continue to secure federal contracts for various services. And, frankly, if the bishops don’t want to serve legally married gay couples on the same basis as straight couples, maybe they shouldn’t get government grants.

The bishops’ brief also brought up the old logical fallacy that legalizing gay marriage will lead to all sorts of other legalizations, like marriage among minors, relatives or polygamists.

No one is seriously arguing for the legalization of any of those things, and having same-sex marriage on the books no more legitimizes incest than does traditional marriage.

Others, like the Family Research Council, said gay marriages can’t fulfill the primary purpose of marriage, which is child bearing.

But what about couples who marry when they are too old to have kids or couples who simply don’t want to have them? Would the Family Research Council support a ban on those marriages?

Still other groups cited historical reasons for supporting DOMA and Prop 8.

“Before 2003, same-sex marriage had never existed in the United States, and it still is comparatively rare,” said the Marriage Law Foundation, a group of college professors, in a brief. “Indeed, before 2000, it had never existed in human history.”

That proves absolutely nothing. Any history of discrimination is wrong, and just because something is tradition doesn’t mean it’s right. Slavery was a “tradition” in America from 1619-1865 and you don’t see many people arguing for the return of that.

Then there’s the Rev. Fred Phelps’ Westboro Baptist Church. There is no question that group spews vile hatred, but at least it is up front about the religious basis for its opposition to same-sex marriage.

“Same-sex marriage will destroy this nation,” the group said in its brief. “If the leaders of this country treat what God has called abominable as something to be respected, revered, and blessed with the seal of approval of the government, that will cross a final line with God.”

American laws should be based on fairness, justice and equality, not religious dogma. Let’s hope the Supreme Court makes its decision based on those concepts and isn’t fooled by sectarian lobbies trying to disguise their doctrines with paper-thin secular farces.