Political waves come unexpectedly. That is especially the case when it comes to the House of Representatives. In 1994, nobody expected the House to flip to the Republicans for the first time in 40 years. The Contract with America was seen as a curiosity, Rep. Newt Gingrich’s (R-Ga.) vanity project. The media roundly lampooned it. And then November rolled around and history was made. In September 2006, George Bush wasn’t that popular, the Iraq War wasn’t going that well, but most pundits and most Republicans thought the House would hold. Then the Rep. Mark Foley (R-Fla.) scandal consumed Washington, and...