WASHINGTON — In 1961, John F. Kennedy said: "In the past, those who foolishly sought power by riding the back of the tiger ended up inside."
In November of 2010, Eric Cantor said: "The tea party are ... an organic movement that played a tremendously positive role in this election. I mean, certainly, it produced an outcome beneficial to our party when you're picking up at least 60-some seats."
Yes, Republican leaders happily rode the tea party tiger when doing so was convenient. Now, Cantor has fallen to the very forces he and his colleagues unleashed and encouraged. After an electoral earthquake that shocked the party's system, the GOP's top brass will be scrambling to figure out what lessons they should draw.
Unfortunately, they'll probably absorb the wrong ones. Rather than taking on the tea party and battling for a more moderate and popular form of conservatism, they are likely to cower and accommodate even more.
Because immigration was a central issue used against Cantor by David Brat, the insurgent professor who defeated him by 11 points, the immediate betting is that House leaders will once and for all declare immigration reform dead for this session of Congress. Governing is likely to become even less important, if that's possible, to House Speaker John Boehner. Just holding a fearful and fractious GOP caucus together will become an even greater preoccupation.
It might usefully occur to some Republicans that Cantor was not their party's only incumbent challenged by the tea party in a primary on Tuesday. In South Carolina, Sen. Lindsey Graham overwhelmed six tea party challengers, securing 57 percent of the vote and avoiding a runoff.
While it's true that Graham did what he could to satisfy his party's ultras — for long stretches, it seemed that not a day went by when he didn't use the word "Benghazi" — he did not, as Cantor did, twist this way and that on the immigration question. On the contrary, Graham defended his support of immigration reform and his vote for a bipartisan Senate bill.
We'll never know if Cantor would have done better if he had held steady on the subject. What we do know is that sending out campaign literature bragging about a news story that declared him "the No. 1 guy standing between the American people and immigration reform" did nothing to placate or persuade those who were out to defeat him.
Republicans who simply want to keep tacking right to maintain their power should also note that if the tea party helped mobilize support for them in 2010, it now threatens to reduce the party to a right-wing sect.
The movement is very good at organizing its own, but it is doing little to attract new voters the GOP's way. If anything, the party's rightward drift is pushing people out. In December 2010, 33 percent of Americans told Gallup's pollsters they considered themselves Republicans. Last month only 24 percent did. Although the turnout was up in the Brat-Cantor race, participation has been low in most of this year's Republican primaries.
Appeasing the tea party could create a vicious cycle: the more the party is defined by a hard core, the easier it will be for the most conservative voters to dominate it in primaries involving only the most ardent.
Cantor actually showed signs of understanding this. He gave speeches, including his "Making Life Work" address in February 2013, that at least acknowledged the need to address the practical worries of Americans who are not particularly ideological and don't wave "Don't Tread on Me" flags.
Politicians, he said, needed to respond to citizens' "real life concerns." These included such basics as "where can you find an affordable home in a good neighborhood to raise your kids?" and "which health-care plan can I afford?" and "will the children make it through high school and get into a college of their choice, and if so, can you afford it?"
Yet Cantor may have been most comfortable on safe conservative ground. He tried to start a practical policy conversation but did not take bold next steps to modify the direction the party took in 2010.
What the tea party giveth, the tea party taketh away. Its energy in 2010 was directed against President Obama and helped Cantor become House majority leader. Now its sights are set on purifying and purging the Republican Party. But purges, as Cantor has learned, are painful. They can also be dangerous to a party's long-term well-being.
E.J. Dionne's email address is email@example.com. Twitter: @EJDionne.