2008-08-11 18:39:51 UTC
1948: Truman (D) vs. Dewey (R). Leader in July: Dewey. Winner: Truman. (July polls incorrect)
1952: Stevenson (D) vs. Eisenhower (R). Leader in July: Eisenhower. Winner: Eisenhower. (July polls correct)
1956: Stevenson (D) vs. Eisenhower (R). Leader in July: Eisenhower. Winner: Eisenhower. (July polls correct)
1960: Kennedy (D) vs. Nixon (R). Leader in July: Nixon. Winner: Kennedy. (July polls incorrect)
1964: Johnson (D) vs. Goldwater (R). Leader in July: Johnson. Winner: Johnson.
1968: Humphrey (D) vs. Nixon (R). Leader in July: Nixon. Winner: Nixon.
1972: McGovern (D) vs. Nixon (R). Leader in July: Nixon. Winner:
Nixon.
1976: Carter (D) vs. Ford (R). Leader in July: Carter. Winner: Carter.
1980: Carter (D) vs. Reagan (R). Leader in July: Carter. Winner: Reagan
1984: Mondale (D) vs. Reagan (R). Leader in July: Reagan. Winner: Reagan.
1988: Dukakis (D) vs. Bush (R). Leader in July: Dukakis. Winner: Bush.
1992: Clinton (D) vs. Bush (R) vs. Perot (I). Leader in July: Clinton. Winner: Clinton.
1996: Clinton (D) vs. Dole (R). Leader in July: Clinton. Winner: Clinton
2000: Gore (D) vs. Bush (R). Leader in July: Gore. Winner: Gore
(popular vote), Bush (Electoral College)
2004: Kerry (D) vs. Bush (R). Leader in July: Kerry. Winner: Bush.
So, out of fifteen elections, the July polls correctly predicted the winner of the popular vote. Pretty good odds for Obama: about a 3-2.