Net approval is only relevant now by proxy, but I thought it interesting to compare Trump's approval rating on the day of the election versus other post-war presidents.
His net approval rating is -8.0
on 538 (+44.6, -52.6).
Of past presidents:
-
Truman went into the
1948 election with a famously negative rating of around -5.9%. However, this was due to bad polling, at a time when polling hadn't really got itself sorted yet. He
won re-election, after which his popularity was +52.
-
Eisenhower was a very popular president, with a net rating of +48.8. He
won re-election.
- Kennedy died, leaving
Lyndon Johnson in the hot seat. He was very much in a honeymoon period at the time of the
1964 election, with a rating of around 59, less than a year after Kennedy's assassination, and
won re-election.
- However, when the time came for
Johnson's re-election (his less-than-a-year in charge before the 1964 election constitutionally allowed him to run for re-election in 1968), his popularity was a net negative, and he
chose not to run. At the time of the election he was around -9.1.
-
Richard Nixon was another popular president in his first term, and was around +32.7 at this stage of his presidency. He
won re-election in a
historic landslide.
- Obviously though Nixon resigned, and
Gerald Ford took over (the only un-elected president). However, Ford's pardon of Nixon was very unpopular, and going into the
1976 election, he was only just about approved of, by +2.3 points. He was
not re-elected.
-
Jimmy Carter won, but was another unpopular president, particularly after the
Iran hostage crisis. At the time of the
1980 election, he was more unpopular than Trump, with a net score of -16.9. He was
not re-elected - Reagan won in a landslide.
-
Ronald Reagan was, like Nixon and Eisenhower, very popular at the time of re-election, at +24.9. He easily
won re-election, again in a
historic landslide against Walter Mondale.
- He maxed out in
1988, when
George H W Bush won (the only time since 1940 that a party won three presidential elections in a row). However, at the time of the
1992 election, the end of the cold war and the US being in recession led to
George H W Bush's unpopularity - he was at -22.9. Added to that, Ross Perot decided to stand as an independent candidate, which sucked up lots of extra votes. Bush
lost re-election.
-
Bill Clinton went into the
1996 election with a popularity of +21.4, and
won re-election.
- In
2004,
George W Bush had lost the massive popularity spike he gained after the September 11 attacks, and was sat at only +1.5. He squeaked through, and
won re-election by just 35 electoral college votes.
- Barack Obama wasn't actually much more popular than Bush after his first term in 2012 - only +1.8 - but
won re-election in the
2012 election by a comfortable margin.
So, in summary, Jimmy Carter and George H W Bush both had negative ratings at the time of going for re-election. Both failed to be re-elected.
Truman had an official net negative rating, but this was probably net positive and hidden by poor polling procedures.
Gerald Ford is the only president to fail to be re-elected despite having a net positive rating (in the same ballpark as Bush Jr and Obama).
Every other president than Ford with a net positive rating won re-election and, in reverse, every other president than Truman who won re-election had a net positive rating beforehand.
Trump does not have a net positive rating.