Final answer:
Trouble on the Mexican border began in the 1830s due to tensions over American settlers in Texas and escalated over the years, including significant violence in the early 20th century and massive deportations in the 1950s with Operation Wetback.
Step-by-step explanation:
Troubles along the Mexican border date back to the early 19th century, exacerbated by American settlers in Texas. In 1830, the Mexican government, alarmed by tensions, prohibited future U.S. immigration and increased military presence. Land and immigration disputes persisted, escalating in the early 20th century, influenced by World War I. In the mid-20th century, the U.S. witnessed a surge in undocumented Mexican crossings.
Notably, the 1954 Operation Wetback aimed to tackle this issue by deporting millions to Mexico. This program, marked by its controversial methods, reflected the U.S. government's attempts to address border challenges. The historical backdrop illustrates the longstanding complexity of U.S.-Mexico relations, shaped by territorial conflicts, immigration issues, and responses to economic and geopolitical shifts over the years.