I understand Trump's concern and what he wants to do, but its futile to try in liberal cities.
I lived in the Detroit area for years and the gov't tried to revitalize Detroit many times, only to have those living in the area destroy time and time again the improvements. Those that live there have no incentive as most are on welfare and haven't worked for anything. They expect if they trash their city, the gov't that owes them will be in to fix it again.
Take also into consideration that we now have a new 'wave' of ILLEGALS, migrants who are now wreaking havoc on our cities; some of them defecate on the streets and sidewalks. So, even IF someone comes in to clean those cities up, it will be short lived til the next round of migrants trash it.
I understand the President wanting a pristine country, but until we actually have people who give a damn about this country and don't expect a free ride and appreciate what they are given, the effort is futile.