By the time the dust finally settled in Virginia's primary election earthquake just 7,212 votes separated the House majority leader, Eric Cantor, from his Tea Party nemesis, David Brat.



Yet the shock upset could have immediate consequences for America's 11 million undocumented immigrants and the already slim chances of a national immigration reform bill that might just have brought them out of the legal shadows.



The narrow margin of Brat's primary win in the prosperous suburbs of Richmond– where barely 5% of the population is foreign-born – makes it hard to judge precisely how big a factor his public opposition to immigration reform ultimately proved in defeating Cantor.



It is also difficult to tell whether the Tea Party's first big decisive win of the 2014 election cycle marks a wider turning point in what had so far proved to be a disappointing year for a conservative bloc that once threatened a string of such primary upsets.



But the imminent removal of Cantor from the corridors of power on Capitol Hill will undoubtedly have one more immediate impact: on the Republican leadership's deliberations over whether to allow a House vote on immigration in the narrow window between now and November's midterm elections.



Buoyed by the Tea Party's weakness until now and opinion polls showing immigration reform would help win over Latino voters, campaigners had been hoping there was a chance that the Republican leadership might finally prevail in its effort to modernise the party in the eyes of non-white America.



Facebook Twitter Pinterest Eric Canto delivers his concession speech in Richmond, Virginia. Photograph: Steve Helber/AP

The House speaker, John Boehner, whom Cantor was tipped to one day succeed, even mocked his Republican colleagues recently for being too scared to take difficult choices over immigration.



The White House had also risked alienating its own supporters by trying to help Boehner bridge the remaining gap and continuing with a controversial deportation policy while a comprehensive reform bill still looked a possibility.



Both the opinion pollsters and the Washington political strategists were humbled on Tuesday night, however, when the Tea Party once again showed its capacity to upset the carefully stacked apple cart.



Just days earlier the Washington Post carried internal polling from Cantor's team suggesting he would win by 34 percentage points.



With strong support from business groups – which back Republlican leaders on immigration reform – Cantor used his substantial funding advantage to run aggressive attack ads against the relatively unknown Brat.



And yet the economics professor who ran on a ticket of standing up to the Washington establishment slayed Capitol Hill's Goliath with a single blow, winning by 56% to 44%.

The longer term prospects for immigration reform, like so many of the other ramifications of the Virginia result, will only become clear in the weeks and months ahead. It is too late in the cycle for Tea Party-supported candidates to sweep aside much more of the Republican leadership before November. Boehner has already comfortably won his primary. Senate targets such as minority leader Mitch McConnell and South Carolina Senator Lindsey Graham have also seen off challenges from the right.

Yet Cantor is a big enough fish in his own right to rekindle fundamental questions about the future direction of the party. Will his defeat empower conservative challengers in the 2016 presidential race such as Ted Cruz and Rand Paul? Will Boehner risk standing up to his conservative wing in future or face a challenge to his own position as speaker?

Will Democrats be able to capitalise on the party's civil war and portray it as far too rightwing for the national mood – or will they too become seen as the same Washington establishment that the voters of Virginia's 7th district so dramatically rejected on Tuesday night?