Most presidents are less popular when mid-terms are held than they are in late spring.
In an earlier piece about the “generic” Congressional ballot question, I presented the trends in support for the parties over the course of the summer for a few mid-term elections. However that question has been asked on a more limited basis than the standard Presidential job-approval question, which Gallup began asking back when FDR served. As I showed earlier, trends in the job-approval question track inversely with changes in the generic-ballot item. Given the tie between presidential popularity and mid-term outcomes, we might ask how the job-approval question has tracked before mid-term elections. Given that President Trump’s approval rating stands at a bit under 42 percent today, where might it be come November?
I have compiled Gallup’s job-approval scores for all mid-term elections back to Harry Truman’s second term in 1950. I have calculated separate averages for first-term and second-term presidents since the additional experience voters have with second-term presidents should limit the effects of most events before the election.
As expected, first-term presidents show a larger change in their job-approval scores than second-termers. Indeed, excluding the anomalous 1974 election after Nixon resigned, second-term presidents saw their popularity grow on average by about a percentage point. Nearly all first-term presidents saw their popularity decline as the election grew near, falling an average of 3.8 percent between May and October.
Among first-term presidents, only Jimmy Carter had an approval rating as low as Donald Trump’s at the end of the spring. Carter saw his rating improve over the course of the summer, but much of that rise came after the Camp David summit with the then-presidents of Egypt and Israel in September, 1978. Otherwise first-term presidents generally see a decline of about four points on average in their job-approval scores as the summer wears on. (Leaving out Carter in 1978 raises that figure to five.) On that basis we might expect to see Trump’s job-approval score in the high thirties come Election Day.
One mitigating factor might be that Presidents who start off with ratings under fifty percent show smaller declines than those with a majority of citizens approving of their performance in the spring. Presidents whose approval score was above fifty percent in May/June watched their ratings fall an average of 4.5 percent by October. For those Presidents, like Trump, starting with a rating below fifty the average decline was just 1.6 percent.