Pew answers the question in their article Ideological divisions over cultural issues are far wider in the U.S. than in the UK, France and Germany by Laura Silver (5/5/2021). In summary (bold added by me):
Across 11 questions on cultural subjects ranging from nationalism to political correctness, the gap between the ideological left and right in the United States – or liberals and conservatives, in the common U.S. parlance – is significantly wider than the ideological gaps found in the European countries surveyed. In some cases, this is because America’s conservatives are outliers. In other cases, it’s because America’s liberals are outliers. In still other cases, both the right and left in the U.S. hold more extreme positions than their European counterparts, resulting in ideological gaps that are more than twice the size of those seen in the UK, Germany or France.
There are a total of eight charts like the one here, plus links to the survey questions and methodology. So, how divided can a country be and still function?