In his important book, Border Wars (MIT Press, 2011) Tom Barry writes:
I found that the border security push has injected new life into the war on drugs by reconfiguring those failed policies as vital components of national security. Immigration control, too, has been swallowed by the security paradigm. Instead of reforming the economic incentives that make illegal immigration inevitable, the United States has been stuffing non-threatening people into for-profit prisons. Counter-terrorism, the ostensible purpose of these undertakings, is an excuse for sheriffs to absorb federal subsidies. And the lack of a coherent border policy provides a vacuum in which reactionary populism and nationalism have flourished at the local, state and federal levels.