Daniel Henninger, opinion editor for the Wall Street Journal, made the argument several weeks back on Fox News that gay marriage could easily lead to humans marrying snakes — or maybe more cuddly animals like dogs and horses first, but animals in any event.

Stephen Colbert sends up this bizarre but persistent Republican

Of course, the smarmy Rick Santorum (still down 18 points in the latest polls) dignified this argument at the Senate level, which might have something to do with why 44% of potential Casey voters cite their disgust for Santorum as their primary motivation.

Now granted, civil unions began in Vermont, a civil rights legacy that went a long way toward erasing the stain of our refusal to put the 19th Amendment over the top when we had the chance.

But let’s not forget that Martha Rainville’s only real competition for the Republican nomination this fall comes from a Vermont State Senator arguing notions not far removed from those of Santorum.

In fact, VDB dubbed Mark Shepard (R-Bennington) “Vermont’s version of Rick Santorum” after a long, odd interview we called “The Initially Amusing, Unexpectedly Queasy Interview with Mark Shepard.” [Photo courtesy of the Bennington Banner.]

On the related questions of civil unions and gay marriage, Shepard and VDB had this exchange:

Shepard: So that’s what marriage is fundamentally about [conceiving and raising children]. And we have a huge breakdown there, you’re talking about huge costs. So I think it’s important to have marriage be about that. If you move it to being about how much you love, well, government has no way of detecting how much somebody loves somebody, number one.

Number two, where do you draw the line? How can you make any defense against any type of group marriage, if you go that way? Polygamy, or whatever else?

If you use the logic that it’s consenting adults who love and care for each other, you can make no distinction between those things. And you open up the gates for anything. Is that where we want to go?

VDB: Well, that was Rick Santorum’s infamous argument: if you allow gay marriage the next step is going to be bestiality. And I think that’s just illogical.

Again, this is no Southern Baptist televangelist speaking. This is a man who has tried his best to portray himself as a Vermont conservative, yes, but one well within the mainstream of political thought here.

And VDB finds that a spooky notion.

If you haven’t read it yet, the entire interview is here. We don’t imagine many of you reading are undecided on the race for Bernie’s seat at this point, but if you are, we’re willing to lay good money that this sit-down will push you off the fence.

Push you pretty hard.