Why the Democrats are going to win the Senate explained in one long and confusing graph (plus also the House)

Last spring, Democrats were set to gain two seats in the Senate, leaving the Republicans with a one-seat majority. With some luck, Democrats might have taken three seats and split control of the Senate, leaving Vice-President Vance to tie-break split votes. Now Democrats not only have an excellent shot at gaining four seats for a one-seat majority, they also have a surprisingly good shot at gaining as many as seven seats for as much as a four-seat majority. That shift took only five months. Cook Political Report documented each increment in their Senate Race Ratings. Here’s my annotated version: Every time a Senate race changed ranking, I illustrated the shift with an arrow. Of the thirteen arrows, twelve are blue, and one is red. And that one red arrow (New Hampshire shifted from Lean Blue to Toss Up in late September) reverted back two weeks later. So that’s a net of eleven blue arrows and zero red. Republicans just keep losing more and more ground. Looking first at the seats…