"We can no longer afford to delay reform," said Republican Sens. John McCain and Edward M. Kennedy in a statement that capped weeks of struggle to find common ground.
President Bush, eager to find some legislative accomplishment in the face of low poll numbers, stepped up his own pressure on Capitol Hill and it seems to be working CBS News White House correspondent Jim Axelrod reports.
The Senate is moving toward President Bush's position: don't just tighten borders, figure out what to do with the illegal immigrants already here.
Mr. Bush said he was pleased with the developments and urged the Senate to pass legislation by week's end.
But the emerging compromise drew fire from both ends of the political spectrum. Conservative Sen. John Cornyn, R-Texas, likened it to an amnesty bill that cleared Congress in 1986, while AFL-CIO President John Sweeney said it threatened to "drive millions of hardworking immigrants further into the shadows of American society, leaving them vulnerable to exploitation."
Still, after days of partisan, election-year rancor, an overnight breakthrough on the future of illegal immigrants propelled the Senate closer to passage of the most sweeping immigration legislation in two decades.
A senior White House aide tells CBS News the president plans to become much more forceful now on getting House Republicans to see it his way on guest workers, so the immigration bill may very well tell us a lot about President Bush's current political condition.
In an indication of the complicated political forces at work, officials of both parties disagreed about which side had blinked. But they agreed that a decision to reduce the number of future temporary workers allowed into the country had broken a deadlock that threatened as late as Wednesday night to scuttle efforts to pass a bill. The change will limit temporary work permits to 325,000 a year, down from 400,000 in earlier versions of the bill.
Senate Majority Leader Bill Frist, R-Tenn., characterized the developments as a "huge breakthrough." Senate Democratic leader Harry Reid of Nevada said he was optimistic about final passage, but cautioned, "We can't declare victory."
Sen. Arlen Specter, R-Pa., chairman of the Senate Judiciary Committee, said: "While it admittedly is not perfect, the choice we have to make is whether it is better than no bill, and the choice is decisive."
Officials described a complex series of provisions: