Tea Partier David Brat, who stunned House Majority Leader Eric Cantor in the Virginia primary Tuesday evening, had gone after Cantor for his focus on Washington rather than his constituents, voting to raise the debt ceiling and other political sins. But his most potent line of attack was on immigration.

Brat continually accused Cantor of supporting "amnesty" -- a term that's radioactive with right-wing voters. 
"With 50 million Americans in their working years unemployed, the last thing we should do is provide amnesty or any form of work authorization to illegal immigrants," Brat told the Richmond Times-Dispatch in a questionnaire on Monday
"Yet, Eric Cantor believes that we need to import more low-wage foreign workers at the expense of lower wages and fewer jobs for Virginia families," Brat told the Times-Dispatch. "Cantor also favors the Dream Act and Enlist Act principles. A vote for Eric Cantor is a vote for open borders and corporate handouts. I pledge to work for all the people of our district and will always oppose amnesty. I support legal immigration, but it needs to be done within the context of the rule of law."
Cantor insisted he wasn't in favor of amnesty, but even his apparent acceptance of some changes -- for example, perhaps allowing citizenship for young people who were brought to the U.S. as children -- gave Tea Partiers a target.

“Eric Cantor saying he opposes amnesty is like Barack Obama saying he opposes Obamacare," Brat said last month, according to the Wall Street Journal

Speaker John Boehner, R-Ohio, has hinted (and hedged) that he would like to bring immigration reform to a vote on the House floor, but Brat's defeat of Cantor will make it clear to other Republicans that support for any kind of reform may be politically fatal. 

Immigration reform activists have been annoyed by what they saw as Cantor's caution; they believed (along with many political observers) that the Tea Party's power was on the wane. Now it's clear that Cantor underestimated how vulnerable even his mild concessions made him. 
“We all know that our immigration system is broken and we should make reforms in a step-by-step approach,” he told the Richmond Times-Dispatch a day before his defeat. “We should be able to find common ground when it comes to securing the border and addressing children who did not break any laws and were brought here at no fault of their own and know no other country as home.”

Just a day ago, that may have sounded like an acceptable, even a strong position. Now it sounds like a death wish. Cantor learned the hard way. Other Republicans are sure to take note.

The White House, which hopes to make immigration reform a part of President Barack Obama's legacy, tried to spin that Cantor's loss was due not to his support for reform but because of his ambivalence about it. Two Obama advisers made the point that, unlike Cantor, Sen. Lindsey Graham, R-S.C. -- a reform backer -- survived a challenge on his right flank in his primary Tuesday. That will not be an easy sell.