According to the well-known Five Thirty Eight polling service, in the coming 2018 midterm elections, the Dems have to defend 25 of their 48 Senate seats while the GOP has to defend exactly eight of their 52 seats.
If "all politics are local" (Tip O'Neil, Democrat Speaker back in the Reagan days), and "Its the economy stupid" holds true, assuming a vibrant economy in 2018, the Dems are in for another butt-kicking.
Read the following tweets from Twitchy, a little known info blog: