Every political pundit in the country is, right now, writing about what House majority leader Eric Cantor's defeat in Tuesday's Republican primary means. But how sure can we be that we know what it means? Essentially none of the pundits, including me, had any inkling that he was going to lose - let alone lose, as he did, by a large margin.
It is easy enough to attribute his defeat to the sentiment among conservatives that Cantor is not sufficiently hostile to an amnesty for illegal immigrants, and that the Republican establishment is too squishy: too willing to raise the debt ceiling, vote for bank bailouts, and so on.
But then why did Sen. Lindsey Graham, who vocally championed the immigration bill while Cantor distanced himself from it, win walking away in conservative South Carolina?
Why did Senate Republican leader Mitch McConnell of Kentucky, who is just as much an establishment figure as Cantor, and more favorable to the immigration bill, thump his primary opponent a few weeks ago?
Was the difference that Cantor was caught napping?
It sure didn't look as though he was taking the race for granted. He spent so much money on attack ads against David Brat, the college economics professor who defeated him, that Brat's supporters took to saying that Cantor was running scared.
Was it then the openness of the primary - the fact that Democrats could vote in it - that cost Cantor the seat? A lot of elections feature loose talk about strategic voting in the other party's primary, but it rarely amounts to much.
I don't have a satisfactory answer yet, but I'm not going to trust anyone who makes a confident pronouncement about what this election means unless he saw this result coming.
Ramesh Ponnuru, a Bloomberg View columnist, is a senior editor for National Review, where he has covered national politics for 18 years, a visiting fellow at the American Enterprise Institute and a resident fellow at the University of Chicago's Institute of Politics.