Basically, the Republican "strategy" on the current self-inflicted looming debt crisis is to constantly sabotage themselves and, eventually, the nation as a whole. Either they will just totally lose completely, or they'll somehow manage, through nihilism and intransigence, to pull out a deeply unpopular "victory" that will end up hurting the already crappy economy. So, basically, everyone agrees that they're idiots and they're screwing themselves. Even people who think the GOP's "let's be very loudly irresponsible and then lose horribly" strategy is more canny than it looks agree that it hurts the "national brand" of the party and will likely lead to them becoming a permanent minority party.
I think, though, that regardless of how completely lost the Republican party is -- and they are well and truly lost, and not currently "negotiating" with anything resembling a coherent plan or unified voice -- they will emerge from the current mess unscathed.
It really doesn't matter how awful the Republicans are, because a) they've got a gerrymandered House majority that is practically guaranteed through 2020 and b) American history teaches us that Americans vote for each party about 50% of the time almost no matter what. The GOP currently can't scrape together national popular vote majorities, and they keep losing gimme Senate races, but that'll self-correct in a couple of years, even if they spend those couple of years acting like lunatics and purposely blowing up the economy. Americans don't really punish political parties for longer than a few election cycles, and they save that punishment for truly monumental disasters. In the meantime, Republicans still control a majority of state legislatures, and they have complete control of the government in 24 states. They have the power to enact the entire conservative agenda in nearly half the country. They're fine. If they blow up the economy, do you know who people -- and much of the press -- will blame? "Congress." Or "partisanship." Or "dysfunction." Or Obama. Bob Woodward already wrote a book about how irresponsible it was for Obama not to somehow force House Republicans to act reasonably and rationally, and he will definitely be happy to write another one.
I know I have been among those who've written that demographics screw the GOP in the medium-term, but they'll find a way to fix it, either by getting objectively less awful on some issues (the good option!), with purely cosmetic fixes (the likely option!) or by finding a way to carve out a new narrow majority without changing much of anything (the "maybe economically prosperous gay and Latino people who hate taxes will suck it up and vote for us" option). The idea of the Republican Party getting replaced, like the Whigs, in our lifetimes, is slim. And unless that happens, they'll return to power, because America thinks one-party rule is unnatural. If they survived Nixon, they'll survive Bush and Boehner.
So, cheer up, National Review cruisers! You'll probably win the House, Senate and presidency in 2020.