American states tend to regularly vote with a majority for one of the main candidates from the Republican and Democratic parties. Some states are described as swing states and attract most of the candidates' attention.
The classification of American states into colors has been known since the end of the 20th century. The perception of some states as “blue” or “red” has been strengthened by a degree of partisan stability over the past years, as 37 states have not changed their partisan orientation since 2000.