I've written about this before but there are reasons to be skeptical that his remarkably stable approval ratings are suddenly headed upwards. The excellent G. Elliott Morris explains in The Economist.
"[E]ven after correcting for demographic biases, pollsters’ data can still be unrepresentative. They may have the right shares of Latino voters and boomers, but nevertheless have too many Republicans or Democrats. This concern is pronounced when an event causes especially good, or bad, news for a political party. At such times surveys can suddenly be swamped with partisans who are eager to voice their love, or hate, for the president.
In the wake of Mr Trump’s acquittal in the Senate, pollsters suspect that such a bias could be affecting polls. Courtney Kennedy, the director for survey research at the Pew Research Centre, says that there is a “strong possibility” that the recent uptick in Mr Trump’s ratings has a wave of optimistic Republicans as its source. She says that outlets can control this problem by adjusting their data to have the correct shares of Democratic- and Republican-leaning voters, but the idea is relatively new and few pollsters have data good enough to perform such corrections.
The Economist’s analysis of polls taken during Mr Trump’s impeachment proceedings affirms Ms Kennedy’s suspicion. In polls that weight their data to represent America’s partisan balance or the results of the 2016 election, the share of adults who approve of Mr Trump’s job as president has risen by half a percentage point since impeachment proceedings began in earnest last October. But in polls that do not, Mr Trump’s ratings have increased by over three percentage points."
Now if we only had a candidate who could take advantage of the fact that Trump is still really, really unpopular and likely to remain so....