" Earthquake. The members are completely shocked," was the reaction of one House Republican lawmaker after Majority Leader Eric Cantor's out-of-the-blue loss to challenger Dave Brat Tuesday night. Trying to grasp the import of what happened, Republicans settled into two schools of thought.

The first was amazement at the sheer power of immigration as an issue in GOP contests. Many Republicans believe Cantor tried to play both sides of the street on the issue, on one side working on measures to ease the way for more young illegal immigrants to move into mainstream American society, and on the other assuring fellow Republicans that serious immigration reform would not happen this year.

"If you've heard of this guy Mitt Romney, you'll know people don't exactly love people who talk out of both sides of their mouth," wrote one pro-immigration reform Republican message maven. "In my opinion, that was Eric Cantor."

To the side opposing Gang of Eight-style reform, the problem was that Cantor too obviously aligned himself with what those opponents called amnesty. "Cantor lost because he represented corporations pushing for foreign workers, and Dave Brat was courageous enough to stand for American workers," wrote one anti-Gang of Eight Hill aide. "Brat proved you can beat the corporate open borders money with his campaign message: 'A vote for Cantor is a vote for open borders and lower wages.' "

Whatever the perspective, Cantor's defeat seems to be the final nail in the coffin -- there have been many -- of comprehensive immigration reform in 2014. "Although it is hard to ever pronounce it dead, given the interests involved, I do finally think amnesty is dead -- at least for this year," writes a GOP House lawmaker.

The other strain of thought among Republicans is speculation about what Cantor's defeat will mean for the House GOP leadership overall. Now that Cantor has gone down, can Speaker John Boehner survive?

The answer is unclear. But what is clear is that many Republican members will interpret Cantor's loss as a sign that the GOP leadership is even weaker than originally thought. "I think you will immediately see a lot of people start to put themselves up for leadership," the Republican lawmaker wrote. "Boehner is weak, and I think you could very well see a completely new slate of leaders next January."

In an interview on Fox News' "Hannity" program, Brat himself described his victory in broader terms. "If you go door to door knocking, the American people know the country is headed in the wrong direction," he said. Brat explained that his initial motivation for the race was the financial crisis; the country's leaders, he said, did not learn the proper lesson from the economic collapse. As far as immigration is concerned, Brat asked, "Why are Republicans so intent on immigration reform? There's no answer that really makes logical sense."

Brat did not comment on the question of House leadership. But his words left little doubt that, should he win office in the general election this November, he will favor far-reaching change. "The only problem with Republican principles," Brat said, "is no one is following them."