Does presidential job approval trend towards 50/50 when they face reelection?

[Mr. Morden]

It’s conventional wisdom that an incumbent’s job approval rating can predict whether they’ll be reelected or not, with a job approval in the high 40s usually being high enough for a president to win a second term.

But is a president’s job approval rating something that actually exists independently of the fact that he’s facing an election?  Or does a president facing reelection cause partisan loyalties to kick in in a way that they hadn’t in years 1, 2, and 3 of his term, and thus (because of the polarized electorate) his approval rating tends to end up close to 50% when election day approaches?

I just looked up Obama’s last job approval # in the final Gallup poll before his 2012 reelection date, and it’s 52%.  For Bush in 2004, it’s 48%.  And for Clinton in 1996, it’s 54%.  All of them had stretches of time in their first terms where they were not so close to 50%.  So is it just a coincidence that they all ended up so close to 50% on reelection day?  Or did voters react to the election campaign by either supporting or opposing them on the basis of their partisan affiliations?

Yes, I realize that this doesn’t work if you look at presidents before Bill Clinton.  But things change.  Maybe the electorate is more polarized now, and a consequence of that is that presidential job approval will always be close to 50/50 on election day.

[Mr. Morden]

Maybe one thing to look at would be the party crosstabs on job approval rating in presidential reelection years vs. other years.  You could look to see if the party breakdown on who approves or disapproves of the prez's job performance is especially polarized when the reelection date is just weeks/months away, and if there's more crossover support at other points in his term.

[Bidenworth2020]

interesting thread