ITHACA, N.Y. -- How have U.S. immigration actions changed since the Sept. 11, 2001, terrorists attacks? What do the changes mean for Americans, and what should be done next?

A report issued this summer by the Migration Policy Institute (MPI) has the answers, although a few of its recommendations may irk some on both sides of the political spectrum, says co-author Stephen Yale-Loehr, who teaches immigration law at Cornell University Law School.

The report, "America's Challenge: Domestic Security, Civil Liberties and National Unity After September 11," examines the U.S. government's post-Sept. 11 immigration measures from three distinct perspectives: their effectiveness in fighting terrorism; their impact on civil liberties; and their effect on America's sense of community as a nation of immigrants. It is summarized and can be ordered at the MPI Web site: http://www.migrationpolicy.org. MPI is an independent, nonpartisan and nonprofit Washington, D.C., think tank.

"'America's Challenge'" is the most comprehensive compilation and analysis yet of the government's post-September 11 immigration measures," says Yale-Loehr. "It offers recommendations that can make us safer and still protect our civil liberties at the same time."

"The report takes both civil liberties and security needs seriously and integrates them into a single framework," says MPI co-director Demetrios Papademetriou, another co-author of the report. "Its recommendations may not please purists on either side, but they are essential if we are to move forward as a society."

"This is a courageous and practical report that requires serious attention by our legislators and policy-makers," says Vincent Cannistraro, former head of counter-terrorism operations and analysis at the Central Intelligence Agency and member of a panel advising the authors.

The report finds that government successes in apprehending terrorists have come not from immigration actions but from international intelligence breakthroughs, information gleaned from arrests made abroad, law enforcement cooperation and interagency information-sharing. It shows that intelligence and immigration policy must work together to combat terrorism effectively. We believe it is possible to use immigration measures more effectively to defend against terrorism, while also protecting the fundamental liberties at the core of American identity," said co-author Doris Meissner, a senior fellow at MPI and a former Immigration and Naturalization Services commissioner (the federal agency is now called the Bureau of Citizenship and Immigration Services). The report advances an alternative policy framework that integrates immigration policy and counter-terrorism. The framework's pillars are improved intelligence, information and information-sharing; smarter border protection; vigorous, intelligence-based law enforcement; and engagement with Arab- and Muslim-American communities.

"America's Challenge" also goes well beyond the scope of the recent report by the U.S. Justice Department's inspector general regarding treatment of immigration detainees. In particular, the researchers managed to bypass government efforts to shroud its actions in secrecy and not identify the 1,200 people detained since the terrorist attacks. They succeeded in compiling information on more than 400 of the detainees, conducting interviews with lawyers and community leaders and surveying press reports, largely in local media.

The report's appendix contains summaries of each of those individuals. The pattern that emerges, consistent with the Justice report, shows persistent violations of due process as well as harsh law enforcement measures directed solely at males from Arab and Muslim countries. The majority had significant ties to the United States and roots in U.S. communities. More than 46 percent of those for whom relevant information was available had been in the country at least six years. Almost half had spouses, children or other family relationships in the United States.

The report also investigates the impact of current measures on U.S. Arab and Muslim communities. It finds that the government's actions have frightened and alienated Arab- and Muslim-Americans, undermining counter-terrorism goals. Programs such as special registration became a vehicle to sweep up even those with minor immigration violations. That has discouraged compliance by raising fears that deportation could be the price of participation and cooperation.

There was one positive response: "The experience of Muslim and Arab communities post-Sept. 11 is, in many ways, an impressive story of a community that first felt intimidated but has since started to assert its place in the American body politic," says report co-author Muzaffar Chishti, a Cornell Law School LL.M. graduate who is now a senior policy analyst at MPI.

The report involved 18 months of research and extensive interviews by Cornell law students and others, with detainees and their lawyers; current and former senior government officials; and Arab- and Muslim-Americans. A blue-ribbon advisory panel included civil liberties, law enforcement and counter-terrorism experts and leaders of affected immigrant communities. Other co-authors are Jay Peterzell, former national security reporter, Time magazine; and Michael J. Wishnie, associate professor, New York University law school. The law firm of Cleary, Gottlieb, Steen and Hamilton gave pro bono assistance.