The electorate has rarely seemed so evenly divided. The latest New York Times/Siena College poll found Harris and Trump tied 48 to 48.
The result, coming less than two weeks before Election Day, and as millions of Americans have already voted, is not encouraging for Ms. Harris. In recent elections, Democrats have had an edge in the popular vote even when they have lost the Electoral College and thus the White House. They have been looking to Ms. Harris to build a strong national lead as a sign that she would do well in such critical swing states as Michigan, Pennsylvania and Wisconsin.