The Twisted Roots of America’s Immigration System (with Lesson Plan)

U.S. immigration is some seriously complicated business.

Contrary to what politicians from both parties often say, there isn't a single line you can just wait in to get a green card and become a permanent resident. As this Above the Noise video makes clear, the process can take years, even an entire lifetime, depending on where you're from, who you know, what skills you have and even how big your bank account is.

So the idea of "going to the back of the line" and waiting your turn doesn't even remotely reflect the reality of what the immigration process actually looks like for most people trying to come here legally.

It doesn't help that immigration is among the most explosively divisive issues in America, one that's easily misunderstood and often exploited for political gain. But there is one thing that almost everyone across the political spectrum -- from President Trump to pro-immigration advocates -- does actually agree on: America's immigration system is sorely outdated and in dire need of serious overhaul.

So how did the system get like this?

Scroll through the timeline below to follow the tangled history of America's ever-changing immigration policies. (Easiest to view in full-screen mode) The interactive chart beneath it shows rates of legal immigration from 1820 to the present (use the scroll bar to zoom into specific chunks of time).

There have been four major waves of immigration to America, the last of which -- mainly from Mexico, other Latin American countries, and Asia -- continues today. Several themes play out consistently in all four chapters:

• Each successive wave of immigrants has been, to some extent, a reflection of social and economic conditions elsewhere in the world, and within the U.S. itself.
• Nearly every cycle of newcomers has faced animosity and backlash from already assimilated communities.
• The history of America's immigration policy is a swinging door that often opens during periods of economic prosperity and slams shut when times get tough.

Immigrants obtaining legal permanent residency, 1820 to 2015

Note: In 1820, 8,385 immigrants legally entered the United States. The Census from that same year listed the total U.S. population at 9,638,453 (of which 1,538,022 were slaves.) In 2015, the U.S. population was roughly 321 million, and there were more than 1 million legal immigrants.

Source: Department of Homeland Security, Office of Immigration Statistics