Immigrant families and children's advocates rally in response to President Barack Obama's statement on the crisis of unaccompanied children and families illegally entering the United States, outside the Los Angeles Federal building Monday, July 7, 2014. A top Obama administration official says no one, not even children trying to escape violent countries, can illegally enter the United States without eventually facing deportation proceedings.

Nothing New in Worry Over Immigration 

American history is filled with worries over surge of immigrants.

Immigrant families and children's advocates rally in response to President Barack Obama's statement on the crisis of unaccompanied children and families illegally entering the United States, outside the Los Angeles Federal building Monday, July 7, 2014. A top Obama administration official says no one, not even children trying to escape violent countries, can illegally enter the United States without eventually facing deportation proceedings.

Immigrant families and children's advocates rally in response to President Barack Obama's statement on the crisis of unaccompanied children and families illegally entering the United States outside the Los Angeles Federal building on Monday.

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Here's a reality check on the immigration issue, which is coming to a boil across the country: It has been one of the most emotional problems America has faced for many generations, and it has always proven very difficult to solve. The same pattern holds true today.

Tens of thousands of undocumented and unaccompanied children have crossed the U.S.-Mexico border in recent months, along with thousands of undocumented parents and their kids. Angry demonstrations and arguments have erupted in the United States over what to do about it.

[READ: Obama Will Go It Alone on Immigration]

Republicans say President Barack Obama made the problem worse by approving policies to defer some deportations and find ways for the children of undocumented workers to stay in the United States. Since then, the flood has grown worse, straining local resources and creating a humanitarian crisis, as undocumented children entered the United States with the expectation that they wouldn't be deported. Obama hasn't clarified his intentions or his timing on deportations but he is asking Congress for $3.7 billion in emergency funding to deal with the crisis.

The current situation seems highly complex and emotional, and that's part of the history of immigration in the United States. As journalist Michael Barone has written for the Wall Street Journal, between 1980 and 2007 more than 10 million people migrated legally or illegally from Mexico to the United States. Barone adds that this influx, coupled with migrations from other areas, unsettled many Americans who feared that the new migrants would bring too much change and destabilize the country as they knew it.

As Barone pointed out, this was only one of many waves of immigration. Others have included people from Northern Ireland and Scotland, Ireland, Italy, Germany, Poland and other Eastern and Central European nations, China and Japan.

And these human waves have stirred fear in many Americans. Even Benjamin Franklin, a founder of the Republic, was infected 250 years ago. Regarding German immigrants, Franklin said, "Few of their children in the country learn English....The signs in our streets have inscriptions in both languages....Unless the stream of their importation could be turned they will soon so outnumber us that all the advantages we have will not be able to preserve our language, and even our government will become precarious." Franklin even said the German immigrants who were arriving in Pennsylvania in the mid- to late 1700s were the "most stupid of their nation." In colonial America and for many years after independence, Catholics from Ireland, Italy, Spain and elsewhere were openly scorned by Protestants and others born in America. Various racial, ethnic and religious groups took their turns enduring the suspicions, hostilities and fears of the native-born throughout American history. Immigrants from Central America and Mexico are the latest examples.

[POLL: Should Unaccompanied Immigrant Children Be Sent Home?]

"[F]or perspective," Barone writes, comparing past hostility toward immigrants to what is going on today, "it is helpful to recollect that the conflicts produced by previous surges of migration resulted in much worse strains. More than that, in the process of dealing with these strains, Americans have developed a capacity and a habit of accommodating and uniting citizens with very serious and deep differences. Going back to the Founding Fathers--with their formula of limited government, civil equality and tolerance of religious and cultural diversity--each new surge of arrivals has been greeted as a crisis without precedent, only to disappear with unexpected speed as the nation faced new challenges."

One hopes this is how today's immigration crisis plays out.