One of the unsurprising things about Gay Marriage coming up as a campaign issue is that we're seeing conservative intellectuals speaking up on the issue, criticising the party's current apparent position on the issue and portraying gay marriage as a positive thing for conservative values.
I imagine it must be frustrating for people in other factions of conservativism to deal with the current prominence of populist and religious conservative views, particularly when the party is led to a stance that's going to be bad for it in the national polls. Conservative support for gay marriage is nothing new; Log Cabin Republicans have been around since the 80s, and neoconservative and libertarian factions of their party have generally at least been open to the idea (as Cheney's support for it demonstrated).
The articles and commentary I've seen online (I keep my eye on political discourse in all sorts of places, across party lines and national borders) seems to be making two solid arguments for a shift in Republican policies on the matter. The first is party-pragmatic; opinions are shifting and the current position jeopardises the party's long-term electability on the national scene. The second is principled: gay marriage helps people make monogamous, stable relationships that for families that choose to raise children will be a more solid family environment.
If the issue remains prominent, I expect the friction within the Republican party to increase over the years, possibly leading to factional rearrangements. I confess to that gut instinct of a socialist to hope that their party remains tone-deaf on the issue and loses forever, but having parts of my family that are conservative (which I realise I've never discussed my sexuality with because it never came up), I don't expect conservativism as a whole is going to go away very quickly and I'd rather just see it stop tugging on society on this issue.
That's my general intuition on shifts in political positions. I don't want to galvanise "the other" party because that party will then take firm stances that, through cognitive dissonance, people subscribing to it will feel encouraged to adopt and defend strongly (most people are not as freethinking as they might claim to be; easier for people like me who don't identify with a party because I'm further left than Dems, harder for most people). Slowly dragging all parties towards what I see as sensible positions is the general strategy I'd like to see us use in a democracy.
Besides, it's not like conservative views are totally alien to us; many of us liberals, even on the far left, can see the value in traditional monogamy, raising kids in stable families, and the like. We're not the same as conservatives on all the details (we generally prefer nurture-and-personal-growth-centric families, they generally prefer discipline-and-achievement-centric families, as one example) and we think they've gotten some of the details very wrong, but these perspectives are not distant enough to generally be alien to each other.
Applied, while I'd rather conservatives simply become liberal (or ideally socialist), because a commitment to social justice is shallow when it doesn't involve building just institutions (and yes, mainstream liberal activists, I'm looking at you too; an ounce of institution is worth a pound of private charity is worth a ton of calling-people-out-and-whatnot; if you're not socialist, your commitment to social justice should not be taken seriously), knowing that's not going to happen I hope they shift their stances on this and support gay marriage. Hoping this sinks their ship neglects that even in legislative defeat (if that can even happen) people will still look to the party-as-flagbearer uncomfortably often to define their views, and if we're going to build a society that ends bullying and marginalisation of non-straight people, having both mainstream parties on board with that will be a major step.