Arguing from Weakness

According to Gov. Mitt Romney of Massachussetts, a 1913 law prohibits the state from issuing marriage licenses to out-of-state applicants if the resulting marriage would be illegal in their home state. The statute was originally enacted to prevent mixed-race marriages.

It seems to me that if your argument rests squarely on an anti-miscegenation statute that had as its purpose a singularly racist goal, your argument is not all that strong.