That’s why I believe one should never get cocky with Trump’s win - it was really very thin (70,000 votes over 3 states). The Democrats will be very motivated to turn out and vote, and with Trump losing some ground among the independents who voted, that’s not good. It’s so important that this Russia thing is wrapped up (which is why Mueller will drag it out), and it’s so important that Trump get his agenda through. That will help a lot. I also think it’s important for Trump’s communications staff to quickly address issues like that gold star widow/congresswoman. I think that could have been cleared up the next morning. The media is going to try to stretch out any “scandal”, and those always lead to a dip in the polls.
Trump lost a LOT of support on day one when he decided not to pursue charges against ‘crooked Hillary’ as he promised. A lot of failures since then have sprung from that lack of resolve.