WASHINGTON — More than a month after Election Day, the biggest political story for many Americans is how close the presidential race was. President-elect Joe Biden won by more than 4 points, but polls and some observers were expecting a win in the 10-point range.Taking a longer view, however, the relative closeness of the race shouldn't have been a surprise. It was less an outlier than standard operating procedure. In fact, the United States is in its longest run of single-digit popular vote elections in a very long time.Biden's 4.4-point victory in November was the second-largest popular vote win by...