The Tea Party keeps jolting American politics, with Republicans struggling to grasp implications of the ouster of one of their political masters who failed to crush an insurrection from within.

House Majority Leader Eric Cantor’s loss in Virginia’s Republican primary on Tuesday to a virtual unknown, Tea Party-backed economics professor Dave Brat, was a Grade-A political bombshell, the biggest shockwave to course through Congress in years.

Whether the upset in a single congressional district can re-energise a conservative grass-roots movement thought to be on the ropes remains a debate among analysts.

But ousting a majority leader from within his own ranks is rare, and the reverberations have jolted Washington, where Republicans have been seeking a united front in opposing policies of President Barack Obama.

“This election should be a reminder to all in Congress — Republicans and Democrats alike — that the conservative base is alive and well,” crowed Senator Ted Cruz, widely seen as the congressional flagbearer of the movement.

Cantor, 51, was waiting in the wings to eventually take the top job from House Speaker John Boehner, who had worked to tamp down conservative uprisings that bubbled since 2010 when an anti-incumbency wave brought dozens of Tea Party-backed candidates into Congress.

Cantor will resign his leadership post on July 31, while the Republican Party’s most conservative faction licks its lips at the prospect of finally winning a precious spot in leadership.

A single battle victory does not win a civil war, however. The anti-tax, small-government Tea Party movement has lost the vast majority of primary challenges against Republican incumbents this election cycle.

“The establishment is winning, and winning quite consistently,” with research showing the Tea Party “is not doing that well in national terms,” John Hudak, an expert at The Brookings Institution, a Washington think-tank, told AFP.

Cantor may have proved the Tea Party movement can still take down trophy prey, but “I think drawing lessons about what it means for Republicans generally is a bit overstated,” Hudak added.

Congressman Peter King nevertheless warned that the party was being “hijacked” by the radical right, which he accused of purposely shutting down government last year over a fiscal confrontation.

House Republican John Fleming said scandals rocking Washington in recent months, including accusations of mismanagement at military veterans medical facilities, is fuelling outrage.

“They are ready to go after anybody that represents Washington. There is very much of an anti-incumbent fever now.”

In Kansas, far-right challenger Milton Wolf aims to unseat Republican incumbent Senator Pat Roberts.

“Eric Cantor isn’t the only incumbent from Virginia who is going to lose his primary this year,” Wolf said in a statement after Brat’s win.

“On August 5th, it’s Pat Roberts’ turn.”