As is often the case with these things, the premise behind this Harper's symposium - that the GOP needs to be shoved into the "well-deserved oblivion of the Anti-Masons and the Know-Nothings" - is more interesting than its contents. But it is an interesting question: We've gone over a hundred and fifty years with the current two-party system, but there's no reason in principle that the GOP (or the Democrats) couldn't go the way of the pre-Civil War Whigs. What would have to happen, though, is not what most Democrats have in mind when they fantasize about politics these days - namely, an enormous Democratic majority and a Republican rump. Rumps are often resilient things (just ask the GOP of 1964, or 1934, or the post-Civil War Democrats), especially when they're centered around a particular regional or cultural identity, as a GOP reduced to its Southern stronghold would be. Political parties are more likely to collapse from internal contradictions than they are to be ground out of existence by a bigger, stronger rival: That's what happened to the Whig Party, which was undone by the Compromise of 1850 and the debate over slavery, and to a lesser extent it's what happened to the British Liberal Party over Irish Home Rule and World War I. In both cases, the party went from a relatively strong position to near-total collapse, thanks to an issue or issues that were big and divisive enough to strike at the core of the party's identity. It's almost possible to imagine something like this having happened to the Democrats had the Iraq War turned out differently, with a left-wing peace party and a centrist, hawkish, McLieberman party emerging from the rubble. It's harder to envision how it would happen to the post-Bush GOP: Obviously, there are plenty of ideological fault lines that could peel various constituencies away, but it's tough to see any emerging issue that could split the party down the middle; it seems more likely that the Republicans' worst-case scenario is a long stint in the political wilderness than a fast train to oblivion.