<img src="https://www.washingtonpost.com/wp-apps/imrs.php?src=https://arc-anglerfish-washpost-prod-washpost.s3.amazonaws.com/public/C6ZHGIXJEMUR5TVAN3EQSYQMOQ.JPG&w=1024" /><br>Since 2009, the number of states with both legislative chambers held at a 2 to 1 margin by one party has more than doubled.