According to Arminian theologian Randal Rauser:
This brings me to an issue I’ve raised at several points in the past. So long as Christians apply to others different standards from those which they apply to themselves and their immediate belief community, they will not have a credible moral voice in the public square.
Oh yeah, and as for that clerk Kim Davis, she’s been married four times. (To be fair, that’s three divorces before she says she became a Christian. But that doesn’t change Jesus’ above-mentioned indictment.)
I've discussed this once before, but now I'd like to approach it from a different angle. Rauser's objection is hardly unique to him, but it's even more inexcusable for him to use it because he is a reasonably sophisticated thinker who's capable of drawing intelligent conceptual distinctions when he wants to. But his desire to assimilate with the cultural elite in this case betrays him into shoddy logic.
Davis's marital status is a red herring. Why? Because this is not first and foremost about her. She's just an incidental player. One face of a cause far larger than herself. The question at issue is not her goodness, but the goodness of the cause which she–among so many others–happens to represent. The morality of a cause grounded is the principle, not the person. A bad person doesn't make a good cause bad.
That should be obvious, but since so many people miss it, let's consider a few concrete illustrations:
Hitler, Mussolini, and FDR all had mistresses. Historians suspect Ike had a mistress. Would it therefore be reasonable to conclude that fighting for Nazism and fighting against Nazism were morally equivalent? Hardly.
From what I've read, Gandhi was a pretty sleazy person. Does that delegitimate the cause of Indian independence? Why should it? That's something you must judge on the merits. If Gandhi were worthier, that wouldn't make the cause any worthier–and if he were less worthy, that wouldn't make the cause less worthy.
I think it's safe to say that Dabney and Thornwell were more personally virtuous than Sherman and Grant. Does that mean the Confederate cause was more virtuous than abolitionism? What a non sequitur.
From what I've read, Martin Luther King suffered from some glaring moral and theological deficiencies. (And, of course, the same could be said for some of his opponents.)
Does that discredit the Civil Rights movement? Not at all. King was never the standard of comparison.