A one-word answer to that question would betray a commitment to ideology over logic.
While it's certainly demonstrable that most if not all of our most impoverished, ill-run cities have been dominated by Democrats for the past 50-100 years, they are only part of a national and world system. Just blaming insufficient spending toward any given area isn't sufficient: we spend more on public education and partially public health care per capita than most other nations for inferior outcomes. Tax policy, fiscal policy, trade policy, regulatory policy, monetary policy and public sentiment all have a role to play (both long ago and current). Anyone who claims to have a comprehensive understanding and cost-effective plan to address those problems is probably misinformed in direct proportion to his/her level of confidence.