In a surprise upset last night, Tea Party candidate David Brat defeated House Majority Leader Eric Cantor in Virginia's primary election.

Cantor raised almost $5 .5 million dollars for the campaign, compared to the $200,000 raised by his competitor, Brat. Some speculators say it was Brat's fierce opposition to immigration reform which clinched his victory, but that might not be an entirely accurate assessment.

Here to explain is Seung Min Kim, who covers immigration and congress for Politico.