Gallup has released its state by state poll. Trump has a record low approval rating for a new President at this point in their first term, as we all know. In fact, he's only above 50% approval in 17 states, and he's under water in 31 states.
Though many of the states are exactly what you would expect (West Virginia loves him/California hates him), there are some states that are very interesting:
State Approval/Disapproval
Ohio 47/48 Ohio is staying surprisingly consistent in its support for Trump. He's only dropped 4.3% since November- that should be a concerning sign for Democrats.
AK 53/40 Trump is still obviously very safe here, but he's dropped 7% in 6 months, which is surprising.
IN 47/48 Trump won Indiana with 57% of the vote. He's dropped 10% in just 6 months and is basically breaking even-bad sign given this is one of the vulnerable Dem seats in 2018
PA 43/52 PA seems to be shifting back left rapidly at this point
GA 43/50 Being 7 points underwater in GA is a potentially concerning sign for Republicans who have been watching GA turn purple pretty rapidly
AZ 43/52 This is a VERY concerning sign for the GOP. Jeff Flake is considered to be one of the three GOP Senators who is vulnerable in 2018, and Trump may be speeding AZ up to purple
TX 42/51 Trump has dropped 10% in Texas in the last 6 months, and, Cruz (who isn't super popular) is potentially vulnerable in TX. Trump's low approval rating could hurt.
FL 42/51 Florida has rapidly dropped its support of Trump- which boades well for the Dems in 2018, who are feeling vulnerable in FL
If Trump's approval ratings stay low, and if Congressional Republicans keep pushing an unpopular agenda...Dems are setting up for a wave election in 2018. A lot can change between now and then, but at this point the GOP needs that to be true more than Dems.