Forrest Gump said, 'Stupid is as stupid does.' More and more these days I am convinced he was talking about the American media establishment. Serious investigative reporting has been replaced by nonstop discussion of the latest polling data, which quickly becomes the conventional wisdom among the media elites. The latest example comes from recent polls that show Republicans are less popular than they have ever been...at least since modern polling began in the 1940's. The most recent poll puts the party's approval rate at around 28%. That's not very good but is it the end of the world for the GOP? Not by a long shot.
Social scientists have been gathering data on the voting habits of Americans for at least 60 years and we have learned a lot over that time. One thing we know is that party identification is the strongest predictor of how an individual will vote in any given election. Republican identifiers vote for Republicans and Democrat identifiers vote for Democrats at very high rates. Additionally, most independents are not truly independents but are weak party identifiers who usually vote for the same party in most elections. The idea of an American electorate that swings back and forth is a myth. American elections are largely driven by structural factors, not careful deliberation by voters analyzing the nuances of public policy.
The problem with all the discussion of the unpopularity of the GOP possibly costing the party the House next year is that no matter how unpopular Republicans are in national polls it doesn't amount to a hill of beans at the local level. Midterm elections are driven by dynamics that are not present in presidential elections. If 2014 were a presidential election year the discussion of Republicans losing the House might be more salient. But it isn't.
The party holding the White House enters every midterm election at a disadvantage simply because partisans affiliated with the party out of power are more motivated to vote and check the power of their opponents. In 2014 this probably means that more Republicans than Democrats will turn out to vote in the midterm elections next year. Those Republicans will vote for Republican candidates no matter how unpopular the party is nationally.
Further, the way most congressional districts are structured provides the party currently holding the seat with an inherent advantage. Democratic supporters are often packed into urban districts that may be 70-80% Democratic, which means that a lot of Democratic votes are 'wasted' electing a Democratic candidate who would win the election anyway. Republican districts are not as compact and often encompass many rural voters unlikely to switch parties regardless of the current popularity of their party.
To be clear, this does not mean Republicans cannot lose the House next year. Anything is possible in politics. Consider, however, that the last two times the party holding the White House gained House seats in a midterm election the gains were 8 seats in 2002 for the GOP and 5 seats for the Democrats in 1998. Democrats currently need to pick up 17 seats to take control of the House. The last time a party controlling the White House won enough seats to take control of the House of Representatives in a midterm election? It has never happened in American history. Does that mean it won't happen in 2014? No, but 225 years of history tells me it is highly unlikely.