That sound you heard is not the Ohio rain that is so often punctuated by a roll of thunder, but existential angst as it works its way through the Republican establishment in Washington, D.C.

Eric Cantor, U.S. House Majority Leader (R-VA), lost his party primary today to political novice Dave Brat, an economics professor from Randolph-Macon College in Ashland, VA. Brat ran to Cantor’s right, focusing, it seems, on illegal immigration. Brat accused Cantor of favoring an amnesty program that would legalize millions of immigrants in spite of their current status.

Fred Bauer, at National Review Online, offers an excellent write-up of what happened and why.

There are a few lessons to draw from this:

1) This is probably the highest-profile congressional defeat since Speaker of the U.S. House Tom Foley (D-WA) lost his re-election bid in 1994. Foley, like many Democrats that year, was subsumed beneath a historic Republican tide. As Majority Leader, Cantor serves as Speaker John Boehner’s (R-OH) right-hand man, making Cantor among the handful of most powerful politicians in Washington, D.C. Unlike Foley, Cantor lost in his primary bid.

2) Incumbents rarely lose in the general election, much less in a primary. Incumbent advantages are dramatic, especially when arrayed against an under-funded novice like Brat. Incumbents tend to be vulnerable when scandals arise or when political conditions change so much that their seats become untenable. For Cantor, it seems, he failed to adapt to the conservative backlash on immigration reform. This is admirable if he was acting on principle. If he was acting on a political calculation, it was foolish.

3) The Republicans should NOT generalize from this result. They will tremble, and their foes will tell them that this portends a trend, but it likely does not. While there are serious rifts within the G.O.P, especially over immigration reform, we have seen relatively few electoral cracks in the party. For the most part, establishment Republicans have won even when challenged in their primaries. Even so, primary results do not easily translate into general election consequences.

In this instance, U.S. House elections are at least as much local contests as they are connected to national issues. With Cantor, it is a little different given his high-profile, but even then, House constituencies are flavored by community concerns. While Cantor’s immigration stance may have hurt him here, his concerns do not translate to other races in the same way.

4) For the most part, this is still shaping up to be a good year for Republicans. With or without Cantor, the GOP will almost certainly hang onto the U.S. House, and they have a slim chance to win control of the U.S. Senate. Cantor’s defeat probably has no connection to November results.

5) What does this mean for the future of the Republican Party? Immigration reform is the hot domestic issue and the GOP establishment seems convinced the party must figure out a way to legalize immigrants so that it can appeal to Hispanic voters in the future. Many conservative Republicans, as well as Tea Party types, oppose any immigration deal that does not begin with stringent border protection. The unknowable question, naturally, is how these dynamics might shape the Republicans’ relationship to America’s largest racial minority during the next generation. We. Shall. See.