Tea Party activists during the "Exempt America from Obamacare" rally held on the West Lawn of the White House in Washington, D.C. on September 10, 2013. Photograph by Mark Peterson/Redux
Tea Party activists during the "Exempt America from Obamacare" rally held on the West Lawn of the White House in Washington, D.C. on September 10, 2013. Photograph by Mark Peterson/Redux

Forget about safe seats. It's true that aggressive Republican redistricting, aided by computers that slice and dice neighborhoods by race, class, partisan affinities and more, has made some conservative House districts unassailable. It's also true that most House districts were unassailable long before anyone ever heard of a Tea Party.

I asked Mark Gersh, who has spent a lifetime targeting House districts for the Democratic Party, how many of the Democrats' 201 seats in the House are "rock-solid." His answer: 175. Of the remaining 26 Democratic seats, Gersh figures only five to 15 -- around 5 percent -- could be in real jeopardy next year.

The point is, House members get re-elected. A lot. In 1,740 House contests from 2002 through 2008, the average margin of victory was 39 points. In the most tumultuous year in postwar history, 2010, 85 percent of the House was re-elected. Since 1986, five different elections have produced overall re-election rates of 98 percent.

Because of the packing of urban districts, Democrats have even more super-safe seats than Republicans. The Smart Politics blog at the Humphrey School of Public Affairs found in 2010 that Democrats held 43 of the 50 least-competitive seats. Yet there is no corresponding radicalism among Democrats, and no corresponding extra-party infrastructure -- Club for Growth, etc. -- designed to bludgeon Democrats into radical conformity.

There are, of course, safe House members who Democratic leaders would love to see disappear -- Google the 12-term Floridian "Corrine Brown" and "corruption" and you can read for hours. But Democrats simply have no Tea Party equivalent.

The fault, then, is not in our districts but in ourselves. Leading Republicans nurtured the Tea Party, viewing it as a hammer to smash the White House. They coyly demurred when asked about repugnant birther conspiracies, maintained silence in the face of racist outbursts and some not only tolerated but advanced what they knew to be lies.

The Tea Party isn't a result of safe seats. It's a product of dangerous politics.

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)