America is a melting pot. Aside from having killer fondue, this mostly means that the U.S. is a nation of immigrants.

People have been immigrating to the Americas since, like, 1492 (and, you know, way before that). From the colonial period to 1882, immigration into the United States was essentially free and unrestricted. Millions of immigrants poured into the country, helping to transform a peripheral outpost of the British Empire into one of the most populous and prosperous nations in the world.

And during the First Industrial Revolution, the United States saw a big wave of immigrants from Western Europe, mostly Ireland and Germany. See, before the Civil War, some parts of the country experienced a growing need for cheap labor. Industrialization (you know, factories and railroads and stuff) required the helping hands of working-class urban folks rather than rural landowners. The North happened to have outlawed slavery, which was good for former slaves, and bad for unscrupulously cheap bosses. 

Who was left to work in dangerous conditions for minimal pay? Immigrants.

Lots of global events around the 1840s meant that people were fleeing the revolutions and upheavals of their home countries. 

• The Chinese empire, for example, was collapsing under European colonialism and revolts, and tens of thousands of people were trying to flee to the United States.
• Revolts and oppression in Germany, Austria, and the Russian Empire were also creating political refugees.
• Most famously, or hugely for this time period, British colonialism in Ireland, combined with famines of the potato variety, led to a mass migration of Irish families to the Northeastern United States.

But immigration always generated opposition, and nativist movements regularly appeared in American life.

So, as usual, white, native-born Americans weren't sure they wanted people who were "different" moving in next door. Not only were they different, which white Americans have traditionally struggled to get over, but they were also competition. Wages were low already, so when a factory owner could pay an immigrant half as much as an American citizen, that was an easy decision for the pocketbook to make.

For these reasons, immigrants weren't always welcomed with open arms and a pat on the back.

Who cares about the history of immigration to America 100 or 200 years ago? 

Sure, immigration today is a major political issue, inflaming strong passions on all sides of the debate over what should be done—or not done—to change our country's immigration laws. 

But America in 1750 or 1850 was a very different country, and immigration issues back then looked very different than they do today. There were no minutemen guarding the Mexican border, no armies of activists marching through the streets of Los Angeles shouting "¡Legalización Para Todos!," and no Spanish spoken in our classrooms or our DMV offices. What can the distant past possibly teach us about the very different world we live in today?

A lot, actually.

It turns out that past immigrant experiences, and past controversies over immigration policy, bear startling similarities to the situation we face today.

250 years ago, Benjamin Franklin worried that a huge wave of German-speaking immigrants then pouring into Pennsylvania would make it impossible for the colony's English settlers to preserve their language or government.

160 years ago, millions of Americans feared that sudden, heavy immigration of a foreign and "inferior" race—the Irish—would undermine the country's Anglo-Saxon social and political traditions.

130 years ago, American workingmen in San Francisco fought to kick out Chinese immigrants who were willing to work brutal jobs for lower wages.

In retrospect, we can see that none of these great immigrant threats destroyed the American Republic. In fact, today most Americans celebrate rather than condemn the contributions made to our economy and culture by German, Irish, and Chinese immigrants and their American-born descendents. But controversy continues to surround the immigration of other, more recent, arrivals to this country.

Is history simply repeating itself, then? You'll have to make up your own mind about that.