Notably, Reagan’s and Clinton’s popular support recovered and both were elected to a second term. Carter’s support also improved in the short term, thanks to a rally in approval after the Iranian hostage crisis began, but as that crisis dragged on and the economy remained weak, his approval rating eventually declined before he was defeated in the 1980 election.

Obama’s re-election prospects should become clearer in the coming months, because Gallup analysis shows that an incumbent president’s 12th- and 13th-quarter averages give a strong indication of whether he will win a second term.