If history is a guide to midterm elections, the party that controls the White House usually loses House seats in the off-year contests and the losses are bigger when the president's job approval rating is below 50 percent.
Gallup looked at its figures
for presidents dating back to 1946 to reach that conclusion -- and pointedly noted that President Obama for the last two weeks has been sitting at a 45 percent job approval rating. Obama's average rating for the year-to-date is 48 percent, compared to 57 percent in 2009.
When presidents are above 50 percent, the average loss of seats for his party in the midterms is 14. When he is below 50 percent, the average loss is 36 seats.
The biggest such loss in midterms since 1946 was in the 1994 electoral earthquake when the Republicans recaptured the House after it had been in Democratic hands for most of the previous 40 years. Then-President Bill Clinton's approval rating was 46 percent -- and the GOP picked up 53 seats.
Ronald Reagan's GOP lost 28 seats in 1982 when his approval dipped to 42 percent and Lyndon Johnson's Democrats lost 47 seats when his approval stood at 44 percent in 1966.
An exception to that rule in recent times was former President Carter, whose approval rating heading into the 1978 midterms was 49 percent, but saw the loss of only 11 Democratic House seats.
Gallup said that in trying to limit midterm losses, "it is unclear to what extent they [the Democrats] will employ the president to help them make that case, though his ability to make a positive impact could be limited if his approval ratings continue to register below 50 percent."
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