Complex sentence: This was the last election during which New Mexico was seriously contested as a swing state, as the Republican Party's collapsing support among Hispanics led to the state being classified as a blue state and voting Democratic by double-digit margins in 2008 and 2012.
Split into simpler sentences: This was the last election during which New Mexico was seriously contested as a swing state. The Republican Party's collapsing support among Hispanics led to the state's being classified as a blue state, as it voted Democratic by double-digit margins in 2008 and 2012.