It's easy to be in general agreement with Maureen Dowd's sentiment:
[T]he fuddy-duddies seemed to be looking for excuses not to make a sweeping ruling.... This court is plenty bold imposing bad decisions on the country, like anointing W. president or allowing unlimited money to flow covertly into campaigns. But given a chance to make a bold decision putting them on the right, and popular, side of history, they squirm.
I too still hold a seething, incurable grudge against "this court" for the W. thing. (This isn't precisely the Bush v. Gore court, but its ideological composition is close enough.) To my mind, the Gang of Five--2000 Version--permanently degraded and for generations despoiled the United States; it unconstitutionally enthroned an unelected blockhead and his malevolent sidekick to the highest offices of the land, which they proceeded to bury in unjust war and unjustifiable debt--and, just for good measure, forever desecrate American honor by blessing torture as official national policy.
So yes, there's that, one "bad" decision which, through the bad guy's subsequent court appointments, ensured the Citizens United decision as well.
It's not quite as easy to agree with Dowd on the specifics, though. In yesterday's case there's the issue of "standing," which, it seems, troubles the court's liberal members. The straightforward trouble: the pro-Proposition 8 petitioners lack a legitimate reason to even be in court. Such a ruling would still leave California's Prop in shambles, however it wouldn't rise to the "sweeping" level yearned for by Dowd and so many civilized others.
The upside? At least the liberals would be obeying, you know, The Constitution--that rare impediment to whatever the "conservative" Justices happen to feel like doing on any given day, in any given way.