A particularly partisan Republican has won a primary challenge that nobody thought possible just a few months ago:
But whatever Lugar's shortcomings or positions, he was less tribal than many. He came to the Senate in a more bipartisan age, shortly before a Republican (Reagan) moved into the White House and constantly reminded his staff, "Remember, boys ... those folks in Congress may be opponents, but they're not enemies." Battles there were, of course - the two American political tribes have been entrenching themselves for generations - but there was still some room for compromise and reason back in the 1970s and 1980s. That room has been vanishingly small and shrinking in recent years.
Some may say that it's a sad day when a politician can win an election for arguing that there is "too much bipartisanship" in Washington. That might be a reasonable campaign position if, by that, you meant that the two parties had between them carved up the system and left everyone else out. But in Mourdock's case, he meant it on a more tribal level: too much working with "them", not enough seeking absolute victory for "us".
But I think the real lesson here is how much the political system has been abandoned by a great many Americans. Indiana is an open-primary state, meaning that on primary day you can show up and ask for whichever ballot you want - you don't register "as" a Republican, or Democrat, or anything else. So there are relatively few barriers here - people who ordinarily vote Democrat, or who are independents, or anyone else, could vote in this race.
In fact, about 650,000 votes were cast - which sounds like a lot until you notice that, according to Federal data, there are 4.9 million voting-age people in Indiana. Meaning that this race attracted the attention of about 13% of the Indiana electorate. And in an open-primary state independents, Libertarians, and Democrats could all have come out to vote if they wanted to - there were precious few races other than Republican ones worth voting for.
So which 13% is going to vote? The ones with the strongest tribal feelings, of course. The lower the turnout, the more that identity politics (in the sense of the party tribes) matters. Which is why parties tend to spend so much time and effort suppressing voter turnout.
One could say, of course, that this is just a primary - and that maybe Democrats didn't vote for Lugar (or even voted for Mourdock) because they think their party is more likely to win the general election for this Senate seat now. While that may be the outcome, voting studies that have tried to prove the existence of such "strategic voting" have found precious little evidence of it.
So here's the Gordian knot to be split: the fewer people vote, the more tribally partisan the system becomes. But the more tribal the system becomes, the less responsive the tribes become to ordinary people, and they less they want to vote. This system serves the parties' interests just fine - but leaves the rest of us out in the cold.