Lawmakers in the U.S. Senate have rejected a handful of amendments that could have derailed a controversial immigration reform plan.

By a vote of 66-29, senators rejected an amendment by Republican Party legislator David Vitter to eliminate a provision that offers legal status to most of the 12 million illegal immigrants living in the United States.

Vitter says the provision rewards people who have broken the law, but Democratic Party Senator Edward Kennedy says legalizing immigrants is important to national security.

An amendment sponsored by Democrat Byron Dorgan to end a temporary worker program after five years was narrowly defeated by a vote of 49-48. Many Democrats are critical of the proposed program saying it will depress wages of U.S. workers, and deny temporary workers a chance to become American citizens.

The Senate also narrowly rejected a proposal by Republican Norm Coleman to allow state and local law enforcement agencies to help enforce immigration laws.

The guest worker program and the opportunity to provide legal status to undocumented workers are seen as the key parts of the immigration reform bill. The Senate approved an amendment Wednesday to reduce from 400,000 to 200,000 the maximum number of foreign laborers allowed to enter the U.S.

A bipartisan group of U.S. senators reached an agreement with the Bush administration last week to provide legal status for undocumented workers, while increasing border security.

An opinion poll, conducted by The New York Times and CBS News, indicates a majority of Americans support efforts to allow illegal immigrants to gain legal status, and to create a new guest worker program.

Mr. Bush defended the measure Thursday, saying it will bring millions of illegal immigrants - in his words - "out of the shadows."