found online by Raymond
From Jonathan Bernstein:
In early 1983, President Ronald Reagan dropped to 35 percent approval. By the end of the year, he was up nearly 20 percentage points, renominated by acclamation and won a second term with 49 states behind him. So anything’s possible for President Donald Trump, who is currently the least popular president at this point in the polling age at 38 percent. It’s very, very early, and there’s plenty of time for him to recover.
But it’s also quite likely that he will draw a fairly serious primary challenge in 2020.