Border Battles
Integrity of its borders is a pretty low standard for a nation to aspire
Maybe it started when the New Deal made the US worker more expensive. Subsequent legislation such as the minimum wage exacerbated the problem. The industrial growth after World War II masked the effects for a while. It became worse when the Great Society created an idle underclass with no reason to work. All the while, various immigration laws made it more difficult for unskilled workers to legally enter the US at a time when corrupt political systems in Latin America exploited them. Then Reagan had to go and fix the economy and the resulting decades of growth created an insatiable demand for workers. And that is how we got a half million illegal aliens marching in the streets of LA.