To make an analogy, anti-miscegenation laws were a horrible injustice but it wasn't "cowardice" of the politicians who favored civil rights to avoid running around the country losing elections left and right over the issue throughout the 1950s and 60s. You want to ask a politicians to take some risks on behalf of a controversial cause, but not so many risks that they lose. Backing the California referendum would have been pure cowardice -- surrendering any opportunity to advance the cause of gay equality in the name of political expedience. What Obama's doing is clever, hard-nosed practical politics.
OKAY, so I was educated in the last century, but back then they taught us that an analogy, while not actually requiring an analogue grounded in some sort of shared reality, was at least not weakened by the occurrence; in other words, we'd like to know what politician was running around the country winning elections by leaving miscegenation out of his call for civil rights. Or name us a white Southern politician who actually ran on the promotion of civil rights and/or an end to segregation, whatever the extent. We'll spot you Richmond Flowers, if you'll agree to tell us what happened when Bear Bryant offered his son a football scholarship.
The fact is that no one had to mention miscegenation in connection with civil rights, and no one could avoid the issue just by not talking about it. "Civil rights" was just another name for miscegenation to large groups of voters.
And the other salient feature of the "debate" is that it was settled by the Court, and not by politicians.
To sum up: were people running around the country losing elections by crusading against anti-miscegenation laws? No. Is that because they felt "miscegenation" was a millstone around the neck of voting rights, employment opportunities, access to justice, and other, more "palatable" rights issues? Maybe some, but--as the commonly accepted wisdom runs these days, except when it chafes to admit it--"those people" didn't vote for you anyway. LBJ famously announced he'd signed over the South to the Republican party along with the Civil Rights Act of 1964. Were there some civil rights "liberals" who nevertheless actually believed the right to marry the person of one's choosing was in fact something different from "civil rights"? Yes. Just as there are today.
So then, let's look the elephant in the eye before the room fills up with bullshit. Is there some figure we can point to, extend the thanks of a succeeding generation to, or put on a stamp, maybe, for his contribution to the advancement of civil rights by virtue of shutting up about interracial marriage? We'll take those crickets to be chirping "No". The mere fact that someone can cough up "miscegenation laws" as an example of the accomplishments of the Civil Rights movement is a tribute to the people who rejected gradualism and legalistic hair-splitting. Martin Luther King's birthday is observed as a national holiday. Roy Wilkins' is not.
Enshrining a distinction between "civil unions" and "marriage" is cowardice. It is pandering without a John. Whose vote does it change? It holds out the promise of mere fence straddling while permanently backhanding gays and lesbians as an expedience with no foundation, not to mention the fact that scant weeks ago Senator Obama was said to be sailing towards the Presidency on the pacific waters of New, Engaged Voters, not on his ability to submarine bigots with doubletalk. Say it again: it's bad enough that you're asked to justify this sort of thing over and over again: Iraq war budgets, FISA flip-flops, AIPAC reach arounds, and Stupid Lapel Pin Tricks. What's much worse is that you seem so eager to oblige.