I think what many conservatives cheering this aren't really seeing the big picture.
At worst, the fact that Virginia has open primaries puts serious doubt as to just why he won the election. If Democrats actually fiddled with the voting and sent themselves out in droves to vote for Brat. Republicans are in for a horrible upset when the election actually takes place. In American politics, spending means winning. Cantor spent 5 million and Brat spent about 1/25th of that. How did he win? He had no exposure. He got verbal support from talking heads but even as the race drew nearer, Cantor was still the clear winner. What happened? Foul play from Democrats? It can't be proved, but it's more than likely. What strengthens my bias towards that idea is the fact that at the last minute, Democrats found a candidate to run against "whomever" won. Suspicious to say the least. Cantor actually knew well ahead of time that Democrats may try to change the outcome of the race. Interestingly enough: Cantor himself accused his opponent of enticing Democrats to do just that.
What's more damaging for Republicans at home is that now Eric Cantor, who may for the most part have been a solid right winger has been replaced by someone who is A) an unknown an B) further to the right. While hardline Republicans may be rejoicing at Brat's win, it'll simply mean that Republicans may now have another uncompromising figure who is not in line with the more center right values of the average American. Will he alienate Independents? Of course he will but he may make up for it by revitalizing some constituents who may have otherwise stayed home.
At best, if this guy won on his own merit (IMHO: plausible, but unlikely) this is a bad sign for Democrats and Republicans alike. It means we might be seeing the start of a shift in politics. Candidates with little exposure, shoe string budgets and zero experience in politics can now win landslide victories by piggybacking the opinions of well known commentators. As implausible as that sounds, it may have just happened and he may be the first in a long line of left wing and right wing candidates who win because of their opinions and not how they vote.
