There has been a lot of talk among Republicans about building a fence between the U.S. and Mexico.

Resident Scholar Kevin A. Hassett

Recent developments in Congress have made final passage of legislation prescribing exactly that more likely before the November elections. Building a fence is a strange move for the party of Ronald Reagan, whose call to tear down the Berlin wall ranks as one of the most memorable lines of the 20th Century.

But it is more than just chicken-wire that some leading Republicans have wrong. Their strong anti-immigration stance is a break from Reagan's vision of America that could have disastrous long-run consequences. Reagan often thought of America as representing John Winthrop's "city on a hill.'"

In his farewell address, Reagan said, "In my mind it was a tall, proud city built on rocks stronger than oceans, wind-swept, God-blessed, and teeming with people of all kinds living in harmony and peace, a city with free ports that hummed with commerce and creativity, and if there had to be city walls, the walls had doors and the doors were open to anyone with the will and the heart to get here.'"

That openness has long been a principal characteristic of our country. In 1920, about 13 percent of the population was made up of immigrants. In 2005, immigrants, both legal and illegal, were estimated to be 12 percent of the population.

Salvation or Enemy?

Such openness is fairly unusual in the world, especially among wealthy countries. In Denmark, even the spouse of a citizen may be stopped at the borders. Many such countries shut their doors to the needy. America welcomes them into a dream, even if they are desperate and hungry.

This stance is absolutely crucial for two reasons. First, because the U.S. is the wealthiest and most powerful country in the world, it is to be expected that citizens of other countries would be wary and envious of our status--and in some cases sympathetic to those, like terrorists, who would harm us.

But if citizens of the world, especially the developing world, know they can become Americans, then America becomes not the enemy, but the salvation. A fence tells the world we are greedy about our success, and wary of sharing it. It fundamentally changes our image in the world, turning the hope of our neighbors into animosity.

Competitive Edge

The second reason immigration is crucial is that it historically offers a tremendous competitive advantage. What kind of person has the courage to leave his home country and head to the U.S.? Economists who model such things generally find that the folks with the courage and wherewithal to move are among the best and the brightest.

If we continually outperform our competitors, a big reason is that we are using their first-stringers. The generally high caliber of our immigrants is visible in the data.

Imagine how tough it might be for you to prosper if we plunked you down in a foreign land. But our immigrants manage, and big time. In 2003, median household income for all U.S. citizens was a bit more than $44,000. New citizens definitely come and find themselves at an initial disadvantage. The median income for first-generation immigrants was only about $27,000.

But the amazing thing is how quickly the children of immigrants melt into the great pot. Second-generation immigrants had a median family income in 2003 of more than $38,000, fully 40 percent higher than that of their parents.

What has always been true about our nation remains true today. We are the land of opportunity, whether your ancestors came from Ireland, like Reagan's, or anywhere else.

The data documenting the success of our immigrants indicate that Reagan's final public words about our country still ring true: "She's still a beacon, still a magnet for all who must have freedom, for all the pilgrims from all the lost places who are hurtling through the darkness, toward home.'"

If America loses that, she loses everything.

Kevin A. Hassett is a resident scholar and director of economic policy studies at AEI.