A poll released on Monday found that Republicans' number one criticism of their own party was that it was "inflexible" and "unwilling to compromise". These respondents should be heartened by two headline-grabbing examples of Republicans bending to accommodate human fallibility: GOP voters in South Carolina accepted wayward spouse and absentee governor Mark Sanford as their congressional nominee and Senator Mark Kirk, a Republican from Illinois, announced that he now supports marriage equality. I'd argue that only one of these anecdotes is about the redemption of a man who's grown as person. If the Republican party wishes to remain relevant and redeem its own image, it would do well to give the cold shoulder to Sanford and embrace Kirk.

At the moment, Sanford is soaking up the party love. He was endorsed by the National Review, most of the top local Republican officials, and Red State's Erick Erickson, who wrote a column pleading for South Carolinians to "show [Sanford] grace," allowing of himself, "I am willing to forgive him. And I'm willing to be graceful."

Sanford accrued that kind support at least in part due to political expediency – a big-name, well-connected veteran politician has better odds in the general election against the formidable opposition of Elizabeth Colbert-Busch. Erickson put the contest in terms of a general Republican malaise, arguing that Sanford "comes back as conservatives in Congress are fighting on all fronts, out numbered, depressed, and needing every man capable of manning the ramparts." If there's one thing Mark Sanford has proven, it's that he's a man capable of manning. Sanford's return to the fold is also part of a familiar narrative arc; his transgression and return may offend some people, but it doesn't challenge them much. We've been forgiving politicians for cheating on their spouses pretty much sense there were spouses to cheat on. And for some reason, social conservatives don't consider breaking a marriage vow as bad as seeking civic recognition for taking one.

Every one of the arguments Republicans made on behalf of Sanford in the primary race would fit – with not much tailoring – easily into a story about Kirk's statement. Take the blunt assessment from a government spending hawk who mockingly scolded a voter for "caring more about Sanford's pants than the precarious fiscal state of the Republic". What a different kind of party it would be if the GOP could expand the not-caring-about-pants sphere beyond Mark Sanford! They might, in fact, get a chance to do something about the perceived "precarious fiscal state of the Republic".

Critics might call the mainline GOP embrace of Sanford cynical, the product not so much of turning a blind eye as not being able to see past the dollar signs (Sanford's national connections and deep roots generated a war chest approximately 15 times the size of his closest competitor). I would encourage top Republicans to put on the same green eyeshade when it goes out to recruit its next generation of candidates: Just how much money will an aggressively anti-marriage equality politician raise? More to the point: is vocal, strident opposition to marriage equality worth in dollar amounts the national scrutiny it will generate? The always-problematic comparison between the marriage equality movement and the fight for black civil rights hits a point of assonance in just how difficult it would be for social conservatives to make any kind of national stand on the issue – and in the near-complete disinterest among Democratic gay marriage opponents in, you know, making a big deal about it. Where is gay marriage's Dixiecrat wing of the Democratic party? Who's their George Wallace, willing to proclaim "opposite-sex marriages now, opposite-sex tomorrow, opposite-sex marriage forever!" I mean, not even Newt Gingrich believes in "opposite-sex marriage forever".

Democrats have flushed out most of the bigots in their elected ranks, and, as I think will happen with Republicans, the rise of the out-of-state fundraising will be weeding out those who would oppose any kind of civil acknowledgement of same-sex unions. Gay marriage opponents are already facing a more literal poverty to go with their deficit of compassion: the group behind the defense of Proposition 8 is $2m in debt. On the state level in last fall's elections, gay marriage opponents found themselves outraised by as much as six to one. What's more, Republican leaders recognize that supporting marriage equality could, let's say, "out" donors who balk at marriage bigotry and who happen to be conservative on other issues. It could "unlock" Republican fundraising in socially liberal states such as New York and California. "Big donors…don't want to invest in campaigns focused on a losing issue," as one GOP strategist put it, and "Republicans' intolerance to marriage equality has been detrimental to winning."

Indeed, the nationalizing of elections has dealt a big blow to profitable Babbitry: "Local/state legislator says dumb thing" is clickbait to online news organizations, and the easy 140-character judgments of Twitter bring national attention and shame to the backwaters where marriage equality – and homosexuality in general – seems like a distant, coastal phenomenon. They probably don't think they know any gays.

I wrote last week about the role that shame is playing in the same-sex marriage debate, and as the Republican party seeks to revamp its image away from the inflexibile fuddy-duddiness embodied by Mitt Romney we can consider money to be another negative force. Gathering more support – or hobbling the opposition – for marriage equality because you've shamed critics into silence, or over-spent them into irrelevance may not be the prettiest way to win a human right, but save your concerns about looking good for the wedding. You can be as dirty as you want on the way there.

• This article was amended on 4 April to avoid ambiguity about the political orientation of the indebted anti-Proposition 8 campaigners