Actually the odds are in favor of the rats in 2020. 33 seats are up and 21 are republican. They defend 12 and we defend 21. They could have a big money advantage and by then may have more illegals ready to vote in red and purple states. Right at the top of my head would be Tillis in N. Carolina. Might be a tough seat to hold unless Trumps coat tails save the day?
From what I heard there seats are harder to defend in tougher areas than ours.
https://www.thoughtco.com/republican-senate-seats-up-for-re-election-3303231
In 2016, Republicans will face an unfortunate problem that Democrats faced in 2014: needing to defend over 20 of their own seats with little chance of picking up any seats from the opposition. In 2014, Republicans had a legitimate shot at more than a dozen Democrat-held seats in red and purple states. The GOP had less than five semi-competitive seats overall, and all of those were in red states. The 2016 slate is a redo of the 2010 tea party wave that saw huge Republican gains in an off-year elecDespite having 24 seats to defend in 2016, things could be a lot worse.
A majority of the seats set up favorably for Republicans. Where the races have a natural Democratic tilt, the Republicans are just really good candidates, not lucky winners who just happened to win because of the Obama-rebellion. It’s very possible that 2016 wind up very similar to 2012. That year, Republicans saw plenty of possible pick-up opportunities, recruited one “electable” candidate after the next, and they all lost anyway..................