The Senate has voted (73 to 25) to limit debate on a broad immigration reform bill, clearing the way for expected passage on Thursday.

The legislation calls for stronger border security measures and the creation of a guest worker program that offers the 11 million to 12 million illegal immigrants in the United States a path to U.S. citizenship if they meet several conditions, including paying a fine and learning English.

Senator Ted Kennedy, a Massachusetts Democrat who played a key role in crafting the bill, expects there will be strong bipartisan support for the legislation when the Senate moves to final passage:

"This may be the most important vote that we cast here in the United States Senate for national security and for our humanity," said Mr. Kennedy.

The bill would divide illegal immigrants into three categories: Those in the country five years or longer could stay and pursue citizenship.  Those living here two to five years could apply for legal status, but only after leaving the country.  Those in the United States for less than two years would be ordered home.

Senator Arlen Specter, a Pennsylvania Republican, defended the proposal, which some critics have called unworkable.

"Is it too unwieldy?  No," he said.  "Does it respond to a very complex set of facts?  Yes.  Is it a way to reconcile a lot of divergent points of view?  Yes.  Does somebody have a better approach?  Not yet."

But a number of Republican conservatives believe the Senate bill is not the answer to immigration reform.  They are particularly opposed to the guest worker provision, arguing that it rewards people who entered the United States illegally with the promise of citizenship.

Senator Jeff Sessions, is an Alabama Republican.

"We have a fundamentally flawed piece of legislation on the floor of the Senate.  It should never, ever, ever become law," he said.

Many in the Republican majority in the House of Representatives agree.

The House-passed immigration reform bill does not include a guest worker provision, and it designates illegal immigrants "felons".  The legislation will have to be reconciled with the Senate bill before a final measure is sent to President Bush for his signature.  Negotiations are expected to be difficult.

Senator Lindsey Graham, a South Carolina Republican and supporter of the Senate bill, believes the House measure is too harsh, and is calling on his Republican House colleagues to bring more compassion to the issue.

"We do not need, in my opinion, as Americans, to have the punishment be such that it will destroy families who have done nothing more than to try to make something of themselves," said Mr. Graham.

President Bush also supports the immigration reform approach taken by the Senate.