A church known as the Evangelical Reformed United Christ downtown in my city once held a public forum at our local pub and brewery, Brewer's Alley, on that very subject. Most who attended all agreed that such an individual - despite all he/she could accomplish, and no matter how qualified - probably could not win public office until society became more secular. They all said that they would not have a problem with it, and in fact welcome it, but doubted it would happen soon.
However, the forum was mostly stacked with progressive Christians, who are very secular as a whole. They de-emphasize the authority of scripture because they do not find the Bible to be without error. The church I mentioned above was actually instrumental in assisting Maryland's new marriage equality act implemented as law by campaigning to gain a majority of voter support in the State. They also have a large body of gay and lesbian congregants, and are a body I tend to visit on Sundays (the fact that the group I hang out with go to Brewery's Alley after service is also a draw for me). ;)
"there is not much that can be done proactively"
But there's a LOT that can be done REactively. Atheists can react loudly to ANY intrusion of religion or mythology (taught as fact) into the government or the education system - not matter how small. Atheists can continue to bring evidence to the table in response to ignorance - even though it may seem futile. I think it's working. Religiously uncommitted people are becoming atheists. The "word" IS being heard - more and more. As the percentages continue to increase in favour of reason, more and more people will start to think about what they'd never permitted themselves to think about before - more than that God doesn't exist, but that God is completely unnecessary. I believe atheism will snowball.
There certainly is one thing we can do, Dale, though I doubt any immediate impact would be forthcoming, and that's to let our politicians know there are other voters out there who are not theists - they may truly not know that, or may believe we are too apathetic to do anything.
There's really only one thing we CAN do about this: stop voting for Republicans.
All we can do is pray ;P