April 2 (Bloomberg) -- Senator Lindsey Graham said his fellow Republicans will be committing ``political suicide'' if they push through Congress immigration legislation that focuses only on building walls along the U.S.-Mexico border and deporting illegal immigrants.

``This is the defining moment for the Republican Party,'' Graham, of South Carolina, said on the ``Fox News Sunday'' program. With Hispanics the fastest-growing group in the U.S., Republicans ``will lose our majority'' if Congress passes harsh penalties for illegal immigrants and fails to create a way of addressing the estimated 11 million undocumented workers already in the U.S., he said.

The immigration debate has split Republicans seven months before elections to decide control of Congress. Graham joined President George W. Bush in urging creation of a so-called guest worker program, while other members of the party, such as Representative James Sensenbrenner, say giving undocumented immigrants legal status amounts to rewarding law-breaking.

The Senate this week resumes debate on legislation to change U.S. immigration laws, including adding a temporary worker program. The House last year passed a measure that would make illegal entry into the U.S. or aiding an undocumented worker a felony and would build a $2 billion, 700-mile barrier across parts of the 2,000-mile-long U.S.-Mexico border. It didn't include the guest worker proposal.

``If we don't stop illegal immigration by securing the border and cracking down on those employers who do hire a lot of illegal immigrants, there just will be more illegal immigrants coming across the border,'' Sensenbrenner, of Wisconsin, chairman of the House Judiciary Committee, said on CBS's ``Face the Nation.''

Consequences

Graham said Republicans will suffer political consequences if they pass a law focusing only on border enforcement and penalties for illegal immigrants. Bush, who won about 40 percent of the Hispanic vote in 2004, and Republican Party Chairman Ken Mehlman have been attempting to gain more support among Hispanics, who historically have given a majority of their votes to Democrats.

``If our answer to the fastest growing demographic in this country is that we want to make felons of your grandparents and we want to put people in jail who are helping your neighbors and people related to you, then we're going to suffer mightily,'' Graham said.

Senator John McCain, a Republican from the border state of Arizona who has introduced a proposal with Democratic Senator Edward Kennedy of Massachusetts that would provide for a guest worker program, said the debate must be handled ``with sensitivity and humanity.''

Demonstrations

``Those thousands of young people you saw demonstrating in Los Angeles were so passionate because they don't want their parents sent back,'' he said on NBC's ``Meet the Press,'' referring to demonstrations last week in Los Angeles and other cities.

Senate Majority Leader Bill Frist, who supports a stronger emphasis on border enforcement, said not all of the illegal immigrants now in the U.S. should be forced to return to their country, especially if they've been here for a decade or more and been integrated into society.

``This is not a monolithic group,'' Frist said on CNN's ``Late Edition'' program. ``To have them all go back home today would be impossible.''

Democrats mostly have supported proposals for a guest worker program. Senator Richard Durbin, a Democrat from Illinois, said on CBS's ``Face the Nation'' that is ``the only way to bring people out of the shadows'' and recognize the immigrants are ``an important part of the economy.'' He called the House legislation ``unacceptable.''

Public Support

An Associated Press/Ipsos poll published today showed that a majority of Americans, 56 percent, favor giving undocumented immigrants the right to apply for some type of legal, temporary worker status. The poll found little support for a border fence, with just 32 percent saying it would work, and 67 percent saying they have no confidence that it would reduce the number of illegal immigrants.

Mexico's President Vincente Fox, speaking on CNN from Cancun where he and Bush met last week, said the solution is cooperation between the U.S. and Mexico on border security and sustained economic growth.

The illegal immigrants in the U.S. ``are being hired by somebody,'' Fox said. ``The U.S. economy needs this energy, needs this workforce. At the same time, we need to do our part to build opportunities in Mexico. If we reach that desired situation, there's no need for walls or other actions now.''

He said his country is working to provide more security on both its northern border and to the south, where people from Central American enter to make their way to the U.S. Last year, Mexico turned back 240,000 people from Central America, he said.

To contact the reporter on this story: Susan Decker in Washington at sdecker1@bloomberg.net.

Last Updated: April 2, 2006 15:18 EDT