<P> Since the 2000 United States presidential election, red states and blue states have referred to states of the United States whose voters predominantly choose either the Republican Party (red) or Democratic Party (blue) presidential candidates . Since then, the use of the term has been expanded to differentiate between states being perceived as liberal and those perceived as conservative . Examining patterns within states reveals that the reversal has happened at the state level but is more complicated locally, with urban / rural divides associated with many of the largest changes . </P> <P> All states contain both liberal and conservative voters (i.e., are "purple") and only appear blue / red on the electoral map because of the winner - take - all system used by most states in the Electoral College . However, the perception of some states as "blue" and some as "red" was reinforced by a degree of partisan stability from election to election--from the 2000 election to the 2004 election, only three states changed "color", and as of 2016 fully 38 out of 50 states have voted for the same party in every presidential election since the red / blue terminology was popularized in 2000 . </P>

When did california become a solidly democratic state