As if Republicans did not have enough cause for optimism this year, the pollster Neil Newhouse offers this lesson from history: Since John F. Kennedy occupied the White House, presidents with approval ratings below 50 percent have seen their parties lose an average of 41 House seats in midterm elections.
This year, a gain that large would return the House to Republican control. President Obama’s most recent Gallup Poll rating: 45 percent.
There’s more. Of Mr. Obama’s last nine elected predecessors, none saw his approval ratings rise between January and October of his first midterm election year.
That points to a Republican breakthrough that would snatch the speaker’s gavel away from Representative Nancy Pelosi — if 2010 follows historical patterns.
But American voters have smashed plenty of precedents lately, most spectacularly by electing an African-American as president in 2008.
“As soon as a political scientist comes up with a sweeping generality about American politics,” said Alan Abramowitz, a political scientist at Emory University, “it will immediately be falsified.”
End of ‘Dead-Ball Era’
Two decades ago, Democratic strategists bemoaned the “Republican lock” on electoral votes for president; in California, the most populous state, the party of Reagan won 9 of 10 elections from 1952 to 1988. But in 1992, Bill Clinton picked the lock — and no Republican has carried California since.
Two years later, the Democrats lost their own redoubt. Led by Newt Gingrich, Republicans won control of the House of Representatives for the first time in 40 years.
For 15 straight midterm elections, from 1938 through 1994, the party holding the White House lost House seats. Then Mr. Clinton’s Democrats gained seats in 1998 — despite the Monica Lewinsky scandal. Republicans did it again under President George W. Bush in 2002.
As Mr. Clinton, Mr. Gingrich and Mr. Bush started their careers in the 1970s, an increase in split-ticket voting appeared to signal the decline of partisanship and the rise of the political independents.
In reality, that phase marked the realignment of partisanship, especially in the South — not its demise. By 2004, Mr. Bush ran a successful re-election campaign on the theory that truly independent swing voters had all but vanished.