“While presidential contests have been consistently competitive since 1988, it’s true that not every race has sat on a knife-edge. For instance, there wasn’t much doubt that Bill Clinton was going to win reelection in 1996, and he won by 8.5 points, the largest margin of victory in the nine elections from 1988 to 2020. But before you doubt that a 10-point margin is a helpful barometer of competitiveness, consider that from 1904 to 1984, 12 elections were settled by double-digit margins compared to just nine by single-digit ones. By comparison, not a single election from 1876 to 1900 or from 1988 to 2020 was a blowout.
It’s no coincidence that the late 19th century is the most comparable period to the present. Few people in the 1880s could mistake a Democrat for a Republican because the parties differed sharply in their views — something that is also true today. Case in point: the last time the average Democrat and Republican in Congress were this far apart ideologically was between the 1870s and early 1900s, according to Voteview, which measures the relative liberalism or conservatism of senators and representatives based on their voting records.”