No matter how the debate on immigration plays out, it's safe to predict that large numbers will continue to immigrate to America every year for decades to come.

As lawmakers debate the Who, How Many and From Where questions of immigration, they also should focus on a largely ignored question: How do we assure that legal immigrants assimilate? How do we assure that they become fully functional citizens whose sense of national identification -- and loyalty -- resides first and foremost with the United States?

President Bush and others have stipulated that assimilation demands that immigrants learn to speak English. Certainly, by acquiring America's common language, immigrants demonstrate a serious effort to become part of our great country. Moreover, research shows that immigrants who learn English earn more, learn more and move up the social ladder much more quickly.

But learning English, while necessary for assimilation, isn't sufficient. Not by a long shot. For America's uniquely successful immigration story is grounded in a deliberate and self-confident policy of forming patriots. While welcoming newcomers, America always has insisted that they learn and embrace America's broad civic culture and political institutions. Only in this way can those who come here truly become Americans.

The recent elevation of multiculturalism as an end unto itself has clouded this essential fact. Lawmakers should clear the air and make the naturalization process more meaningful, emphasizing the laws and processes meant to assure that newly minted citizens are not just "of good moral character," but also "attached to the principles of the Constitution of the United States, and well disposed to the good order and happiness of the United States," as it says in the Immigration and Nationality Act (INA).

Full citizenship requires an understanding of our national history, political ideas and institutions. The native born are supposed to receive that understanding via education at home and in school. Immigrants must be schooled in our nation's first principles -- the Declaration of Independence's insistence that legitimate government is grounded in the protection of equal natural rights and the consent of the governed -- and how the Constitution and our institutions of limited government work to protect liberty and the rule of law.

America's principles are the defining characteristic of its national identity. But the Founders also understood that sustaining the national identity requires a thriving civil society.

Immigrants cannot become fully American by creating enclaves, associating only with others from their native land, speaking only their native tongue and hewing to their native customs. Acquiring the habits, practices and spirit of America requires extended interaction with native American citizens encountered not just in the workplace but in local institutions such as churches, schools and civic and social organizations -- the building blocks of civil society.

Although many immigrate in search of freedom, most come for economic opportunity as well. And their success will be an important factor in their assimilation. The fruits of hard work and entrepreneurship will bind immigrants to their new home. The best we can do for new citizens is to offer them a hand up rather than a handout. We need to make sure immigrants, especially the poor and low-skilled, are not drawn into the perverse incentives of the modern welfare state, whose policies discourage self-reliance, family cohesiveness and financial independence.

Assimilation is necessary to foster not only "that temperate love of liberty, so essential to real republicanism," to use Alexander Hamilton's phrase, but also to establish a genuine attachment to this country and to these people. The objective is for the immigrant to come to regard this nation as my country, to develop an enlightened patriotism based on an understanding of and commitment to America, what it stands for and who we are as a people.

The result of immigration policy throughout American history has been to strengthen our social capital, expand our general economy and provide constant renewal of this national purpose. America has been good for immigrants, and immigrants have been good for America. But this policy can succeed only if we revive the one policy that makes American immigration work, and get back to the hard and noble task of making citizens.

Matthew Spalding is director of the B. Kenneth Simon Center for American Studies at The Heritage Foundation. He is the editor of The Founders' Almanac (2001) and executive editor of The Heritage Guide to the Constitution (2005).