In 1823, President James Monroe, in the face of new republics emerging in Central and South America from former Spanish colonies, called for Europe to remain out of the Americas and not to intervene in the nascent countries. This decree, called the Monroe Doctrine, essentially divided the world into two hemispheres, with the United States at the helm of the West.
In 1963, President John F. Kennedy signed an executive order that transferred command of the Alabama National Guard out of the hands of Gov. George Wallace and into his. Under Kennedy's authority, the National Guard was ordered to protect two Black 20-year-old students, James Hood and Vivian Malone, as they entered the campus of the University of Alabama to enroll and begin desegregation of the school.
In 1964, most elderly and poor Americans didn't have health insurance. That year, President Lyndon Johnson issued his Great Society social reform package. The Great Society, among other things, created the federal health care programs Medicare and Medicaid. By 2019, nearly 40 percent of all Americans were receiving health care through these programs [sources: CMS, National Committee to Preserve Social Security & Medicare].
In 2012, President Barack Obama took executive action to halt the deportation of undocumented young people who had been brought to the U.S. as children. Under this immigration policy, known as the Deferred Action for Childhood Arrivals, or DACA, these people were also allowed to apply for work permits [source: Glastris and LeTourneau].
The actions of each of these men and all other presidents helped shape the world as we know it today. Often, these world-changing events resulted from a simple signature or a public address. But none of these changes could have been made were it not for the one thing each of these people had in common, that each was president.
How did this office become so powerful? How has it changed over time? In this article, we'll get to the nuts and bolts of how the U.S. presidency works and its evolution from the head of a nation to arguably the leader of the free world.