"The Tea Party has been a tremendously positive input, I think."                                                    --Eric Cantor, November 10, 2010

The election of 1820 was the beginning of the “Era of Good Feelings.” The Federalist Party of Hamilton, Washington, and Adams barely even existed and did not even field a candidate in the presidential election. James Monroe was re-elected by virtual acclamation without even having run a campaign. And the young Republic appeared to have licked, once and for all, the problem of political faction.

In 1820, everybody was a Republican.

But, as it turned out, not everybody was the same kind of Republican. The party of Jefferson controlled the country, but nobody could control the party of Jefferson. The next two presidential elections — both between Andrew Jackson and John Quincy Adams (and, in 1824, Henry Clay) — would be among the most bitter and divisive political contests in history.

The Republicans would fracture into the “Democratic-Republicans,” who would go on to call themselves “Democrats,” and the “National Republicans,” who, out of hatred for Jackson, would borrow the name of the British anti-monarchy party, the Whigs.

And all of this had been worked out — in general outlines but not in specific terms — by James Madison in one of the most important works of political theory ever written by an American: the magisterial Federalist #10.

Federalist #10 is Madison’s argument for a strong central government. The greatest danger to a republic, he argues, is a faction (a party or interest group) that becomes too powerful and begins using the power of the majority to oppress the minority. The only way to keep this from happening, Madison believed, was to place so many factions in competition with each other than none of them ever held power long enough to become oppressive. And the only way to do this is to create a large enough political entity to make sure that factions are always unstable.

Which brings us to Eric Cantor, the House Majority Leader whose defeat last night in the Virginia District 7 primary has sent shock waves throughout the Republican Establishment. In one sense, it truly is an unprecedented event. No house majority leader has ever lost a primary election before. Not ever.

In another sense, though, it is exactly what Madison predicted — and exactly what is supposed to happen when a single ideology becomes too powerful.

Make no mistake about it, Cantor was a real conservative. His ideology was as pure as it could be for somebody who also has the responsibility to govern. But that in itself is problematic, since governing under the Constitution requires compromise, while ideological purity forbids it.

But it was not governing the country that finally did Cantor in; it was leading his party. Like most pragmatic Republicans, Eric Cantor understood that his party could not remain nationally competitive unless it could find some way to capture some non-trivial portion of the Hispanic vote, which is the fastest growing bloc of voters in the country and one whose social and religious sentiments should be compatible with the Republican mainstream.

But he also knew that Republicans had damaged themselves badly with Hispanic voters by their persistent anti-immigration stance. He embraced immigration reform carefully and pragmatically because he understood that, without it, the Republican Party could be virtually shut out of national elections for the next two generations. It was a politically astute decision, and it cost him his political career.

As of this morning, Eric Cantor is out of Congress and immigration reform is dead.

The tea party appears to have more power within the Republican Party than it ever has, and establishment Republicans will increasingly have to choose between their long-term political fortunes and their short-term survival. The more success the conservative movement has immediately, the more ideological purity its true believers will demand, and the less successful it will be ultimately. Short term victories work directly against long term domination.

Everything, in other words, is going according to Madison's original plan.