International migration from Mexico to the United States has been driven by both push and pull factors. Push factors in Mexico included lack of economic opportunities, poverty, and lack of access to education and healthcare. Pull factors in the United States included abundant job opportunities, higher wages, and better access to services. The Bracero program initially brought Mexican workers to the US as guest workers to address labor shortages, but many overstayed their visas and became undocumented immigrants. While US businesses benefited from cheaper labor, American workers opposed immigration due to fears over jobs and cultural issues. Over time, undocumented immigration from Mexico significantly increased despite various reforms and policies.