No one really knows why these powers started to emerge. Some people assume the meteor that crash landed in what was then known as Illinois was the cause, but no one really knows for certain. However, these people were not well liked, and for good reason.
While most of them either did not use their powers, or if they did it was in a non-malicious way, others took full advantage of the situation. This caused the government to step in. People were forced to hide their true nature; this didn't stop the bad ones though.
Eventually the people revolted. The law abiding citizens felt it was unfair they were being punished for the crimes of their unsavoury brethren. Vigilantes rose up, finding that their powers were better suited to thwart those who refused to do good than to keep them suppressed. This lead to a battle of "good" versus "evil" and in the process the United States itself changed. War raged for years as the two sides struggled to topple one another. This vastly changed both the political and physical climate of the country.
We as a people completely overthrew the old government and now a new one takes its place, one where these good guys with powers are in charge. They promise to keep the peace and this new country safe. These former vigilantes are now forming a specialized team in order to keep the peace. Former CEO and Inventor Danielle Greenwood was given the task of assembling said team.