This chart shows the results of a new Economist / YouGov Poll -- done between September 17th and 19th of a random national sample of 1,500 adults (including 1,292 registered voters), with a margin of error of 3 points.
Democrats can take heart that they are 6 points ahead of Republicans in the generic vote (39% to 33%). But that is not enough to carry the day in 2018 (and flip control of Congress). There is still a significant 19% who say they are unsure how they would vote, and that 19% could decide the election (if most of them break the same way on election day).
The message Democrats should take from this is twofold.
1. It's not yet time to celebrate, because Trump having low numbers does not insure victory in congressional races.
2. And there's a lot more work needing to be done before November of 2018.