The new Democratic Party-led U.S. Congress is again taking up the issue of immigration, following last year's defeat of comprehensive immigration reform by the Republican-led House of Representatives.  Lawmakers, however, are still arguing over how to handle some 11 to 12 million illegal immigrants already in the United States.


Homeland Security Secretary Michael Chertoff says the Bush administration's initiative to boost security along the southern U.S. border, called "Operation Jumpstart,? has made great progress in deterring illegal immigration from Mexico and other countries.


"In the three quarters of the year that have passed since we put into effect ?Operation Jumpstart?,? Chertoff said, ?we have seen in each quarter a significant decline in the number of people that we are seeing crossing the border illegally and an even more significant decline in the percentage of apprehensions that reflect non-Mexicans."


Chertoff told a Senate Judiciary Committee hearing Wednesday that effective control of the U.S. border is a critical first step in overhauling the nation's immigration laws.  He said the Bush administration wants to work with the new Democratic-controlled Congress to pass comprehensive immigration reform.


But both Democratic and Republican senators say immigration legislation is unlikely to succeed unless lawmakers can agree on how to bring millions of undocumented workers out of the shadows.  Many Republicans and some Democrats fear immigration reform will provide amnesty to illegal immigrants and cause a surge of foreign workers into the country.


Senator Arlen Specter, the ranking Republican on the Judiciary Committee, said "the big obstacle we faced last year was the issue of amnesty.  And if someone has a better idea on how to handle these 11 million undocumented immigrants, we're open to suggestion."


Last year, President Bush supported immigration reform legislation that passed in the Senate, but the bill was rejected by the House of Representatives.  The Democratic chairman of the Senate Judiciary Committee, Patrick Leahy, says the Bush administration must do more to publicly demonstrate its support for an immigration overhaul.


"I believe it can be done.  I believe if it's not done, we have a problem in this country that will actually hurt us,? Sen. Leahy said.  ?It will hurt us as being the great country that we are and we will lose the chance to have the kind of diversity in America that has made us strong throughout the years."


Some measures being considered include a guest worker program, tighter workplace enforcement of immigration laws, and giving illegal immigrants a path to U.S. citizenship.