U.S. midterms are a rebuke to the Republicans, but not the wipeout they deserved

By the standards of American elections, this was an earthquake. The two-party system is so entrenched, and American voters' political identities so immovable, that shifts in the balance of power in any given election tend to be muted.

So the Democrats' gains last night are, in this context, historic. When all the votes are counted, they will probably emerge with at least 45 more seats in the House – the biggest swing to the party in any election since Watergate. They may also take as many as nine Senate seats from the Republicans – matching the largest Senate gain for either party since 1958.