Actually, the DNC knows it's a broken party right now. They've finally rid themselves of the Clinton "don't ask, don't tell" non-sense, and are now cleaning house.
The shutdown was not good. As much as the mainstream media is trying to spin it as, "Congress is broken," even outlets like CNN are totally exposing how the Democrats didn't sign last week, only to sign this week for virtually nothing gained (deadline to 'address DACA' just moved up 1 week). They ended up accepted the same, Republican deal on child healthcare coverage, they offered before the shutdown.
So the question is ... can the Democratic party change things around by the 2018 mid-term elections in the 2nd half of this year? That, plus, how much will people look at the tax changes as they see more in their paychecks, all while corporations are having major, tax-related charges this year.
I know people make fun of Trump, and he's definitely the negative target of 85% of the mainstream media right now. But all that negativity is also what got him elected, and if the media keeps harping on things like the shutdown and the tax code changes, and people see it differently, it could really hurt the DNC.
The only thing the DNC has going for them is that they recognize the problem. Even some are starting to question how much the mainstream media is hurting them too. Most Americans dislike the mainstream media as much as the President, and if the President's numbers continue to rebound, he may be more popular than the media and the DNC by November.
It will be interesting to watch what happens. As The Atlantic warned, the more the mainstream media bashes the new tax code, the more they may see a repeat of the Republican bashing of the ACA -- because people may like the tax code benefits, just like the ACA benefits, as they start to receive them.