Reply #168: The article specifically addresses this.

[donco6]

"How real are these differences between marriage and civil unions, given that a
federal law and some state laws discriminate against all marriages of same-sex
couples? Would any of this change immediately with marriage of same-sex couples?"

Probably not, because married same-sex couples will face other layers of discrimination against their marriages.
Right now, a federal law denies recognition of same-sex unions conferred by any state for purposes of all federal
programs and requirements and over 30 state laws do the same. Ending discrimination in marriage does
not mean the end of all discrimination, but using the term a "marriage" rather than a "civil union" ?is an
essential first step to opening the door and addressing whether continued governmental discrimination
against civil marriages of gay and lesbian people makes sense.

This is referring specifically to the impact of DOMA on state laws.