Open borders
Open borders is the belief that freedom of movement is a basic human right. It's a radical notion that national bounderies are unjust and that migrants of any other culture should be embraced. Immigration laws are to be ignored, tolerance for foreign customs must be embraced, integration into a new society is not observered out of respect and compassion for multicultural ethnic groups.
No borders means no country. No country means no identity. No identity means a sovereign nation ceases to exist. Illegal immigration destroys the fabric of society.
In American politics, both political parties support Open borders. Republicans want access to cheap foreign labor for special interest groups and large donors. This drives wages down or wages remain flat for the rest of the population. Democrats want Open borders to expand voter roles and grow government. Creating a larger government increases power for those holding political office and access to more and more tax money.
Open borders results in more crime. In addition, capital resources are spent on migrants, most of whom have little or no education. Jail populations swell, the health system is burdened, schools struggle to cope, law enforcement and the courts are overwhelmed.