WASHINGTON — Tea Party invaders have finally scaled the high walls and taken their first stronghold inside the GOP castle.

The defection of Florida’s governor from his own Republican Party in the race for the US Senate is an enormously significant victory for this sprawling movement of ragtag patriots.

As an independent, Gov. Charlie Crist is finished.

The de facto GOP nominee, Marco Rubio, is already ahead of Crist and the presumptive Democratic nominee in the polls. His numbers will only rise with additional rank-and file GOP supporters in the wake of Crist’s abandonment of the party.

The Tea Partiers have never managed to win anything this big.

Scott Brown’s victory in Massachusetts was a bigger prize, but Brown was more establishment Republican than Tea Partier.

For Democrats across the country, the Tea surge in Florida should be a startling wake-up call that these people are not the wild-eyed angry mobsters Democrats desperately try to portray them as.

As we saw in the unwavering support for Crist’s conservative rival, Rubio, Tea Partiers can be highly organized, maturely disciplined and — most important of all — they can actually win.