“Members from the other party were once more willing to give a new president some benefit of the doubt early on — or at least, their opposition was not quite so baked in, as the figures for both Bush and Barack Obama suggest. What’s more, there hasn’t been a corresponding change in how strongly the president’s own party feels about him. Members of the president’s party overwhelmingly support him, but there hasn’t been an uptick in those who say they strongly approve of him.
This lack of crossover support for presidents in their first term in office points toward one of the most animating forces in American politics today: Increased disdain and hatred of one’s political opponents, known as “negative partisanship.” As the chart below shows, opinions about the other party have become far more unfavorable since the late 1970s.”
…
“Such hostile sentiments reflect a world in which each major party increasingly believes the other poses a threat to the country’s well-being.”
…
“such deep dislike will likely keep Republicans opposed to Biden regardless of his administration’s actions. It also means that like Trump, Biden will likely have to rely on his own party’s support to buoy his overall numbers.”