[Solve two problems at once; build factories and facilities in South America (Guatemala, Mexico, Nicaragua etc.) and import the goods from there, plus give the local populations a reason to stay there and build their own countries up because their economies and standard of life improves.]
https://www.reuters.com/article/economy-mexico-wages-idUSL2N0CR1TY20130404
The reasons they are sh*tholes is because of their economies and their government corruption. The problem in our inner cities is a microcosm of the problems in these countries. This approach would change that dynamic dramatically. Most people just want to raise their families and have a decent life no matter where they live.