First and second term approval since 1945. The vertical line marks the second inauguration.
Each president has ups and downs. The figure above plots the first and second term approval in the Gallup poll since Truman. The data are available free at the Roper Center here. Scroll to the bottom of the page for presidents prior to Bush. The Gallup Poll web site also has a Presidential Approval Center page here (subscription required) which has party breakdowns and the trend for President Bush. I'm sure they have the data for past presidents also, but I couldn't find them in a quick check.
As I showed in an earlier post here, the second term approval rate has been worse on average than the first for three of the five two term presidents in the post war period (not counting Bush who still has 39 months to go before we know the answer to this.) Of these, Nixon and Truman had uninterrupted declines. Eisenhower had a bad first two years of his second term, then rebounded only to decline somewhat towards the end of his term.
Reagan's second term had two years of bliss--- steady and high approval. Then the Iran-Contra scandal hit, and you can see the nearly instantaneous drop of some 20 points right after the 1986 midterm election. Reagan only slowly recovered from this, trending up until the very end of his term when he enjoyed a final lift in approval to his old levels.
Clinton, by comparison, enjoyed long term positive gains in approval. When the Lewinsky scandal struck he suffered only a 10% approval decline. Even impeachment had only a modest effect on his approval ratings, which remained near 60% in his last two years. The contrast with Nixon is, of course, striking. Nixon was driven from office by collapsing ratings and the threat of impeachment. Clinton was impeached, but never lost the support of the public, and of course was not convicted by the Senate.
Another aspect of the second term is its variability. Despite their second term scandals, Reagan and Clinton has less variation in their second term approval ratings than in their first. Reagan's standard deviation was 7.6 in the first term, 6.7 in the second. Clinton's were 5.6 and 3.9. Truman also had a smaller standard deviation in the second term, but that came from the highly erratic trace of his first term rather than any good news in the second term. Not surprisingly, Nixon's second term was far more variable than his first (standard deviations of 5.1 and 12.0 in the first and second respectively.) And Eisenhower was only a bit more variable in the second term, 5.1 and 5.8 in first and second.
So, if the second term is not generally worse than the first in mean or median approval, and the second term is not generally more variable than the first (2 of 5 are more variable), and if in the face of scandal some presidents can rebound (Reagan and Clinton), though others resign (Nixon) I think we should say that, at least when it comes to public opinion, there is precious little evidence to support commentary which presumes a systematically worse second term than first.
If President Bush suffers in the polls, or if he rebounds, it is a matter of the politics he makes and the circumstances he faces, not a systematic tendency for second terms to go badly.
