"Life, unauthorized" is a series from WHYY/NewsWorks that looks at the personal immigration stories of individuals who are living in the Philadelphia region without legal status. The United States has had an uneasy relationship with immigration throughout its history.

America may be a melting pot of immigrants from around the world, but xenophobia has poisoned the pot for centuries.

Philadelphia's own Ben Franklin, responding to waves of immigrants, wished to ban "swarthy [German] boors" and "blacks and tawneys" from America. "I am partial to the complexion of my country, for such kind of partiality is natural to mankind," he wrote in 1751.

Despite such biases, foreigners have flocked to the United States for centuries. More than 43 million immigrants live here, making up 13.5 percent of the nation’s total population, 2015 Census figures show. That’s up from 2.2 million foreign-born people in 1850, the first year U.S. Census-takers asked people where they were born.

U.S. leaders have grappled with how to respond to the flow of foreigners into the United States, sometimes welcoming them, but more often trying to restrict immigration through legislation that occasionally has had disastrous results. Learn about the history of U.S. immigration in the interactive timeline above.

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