For a fairly liberal (but definitely variable) state, that seems about right. What does that mean?
A ban on gay MARRIAGE would likely pass and be written into the constitution. (I think it would pass in all 50 states, 9 of 10 Canadian provinces if the vote came up and most Western countries)
A deeper legislation banning civil unions as well would have a harder time passing. It would be a squeaker...it may only come up with 45% or so.
Something WILL happen though, and it won't be legal gay marriage. (Massachusetts was a fluke, I don't think it will stay there forever)
I think you underestimate the civil union ban. EVERY state that also baned civil unions had that pass with ease.
Personally when I explain how civil unions are just homosexual marriage without the M the person generally "gets it". (unless they have been a leftist lawyer)
In fact the "whisper" at the last bar convention has been that judges would just allow marriage to stand and impose marriage lite by going "around" the constitutions. Thus a ban on civil unions is no longer a potential compromise. it is inevitable.