Explain why urban renewal has both a positive and negative impact

"However, urban renewal programs can also have negative effects on social and physical environments by contributing to unsustainable increases in property values and lifestyle costs, leading to social exclusion, gentrification and displacement of long-term residents of lower socio-economic (SES)"

the only other powers were germany russia and uk and they were too busy fighting each other wearing each other down   that the us was becoming strong and they were becoming weaker