ROSSLYN, Va. -- When Kim Wade pulled up in front of the Jackson, Miss., offices of Republican Senator Trent Lott, a crowd was already waiting.
They were students, professionals, and homemakers, all members of the advocacy group NumbersUSA, which wants to restrict immigration. And they were there to blast Lott for his support of the Senate immigration bill.
The group delivered petitions bearing nearly 3,000 signatures, imploring Lott not to "sell out Mississippi to illegal aliens." The office was also flooded with phone calls protesting Lott's immigration stance, said Wade, a local talk-radio host.
Television , radio, and Internet ads condemning Lott had been running for days before the visit last Tuesday . By Friday, 1,000 more people had signed the NumbersUSA petition online.
Conservative anger at the Senate immigration bill is at such a pitch that even Republican lawmakers are feeling the heat. Groups like NumbersUSA have been channeling that grass-roots fury and, in doing so, have leaped in size and are playing a larger role in the immigration debate than before.
A crucial vote on the bill to overhaul the nation's immigration laws could come as early as tomorrow in the Senate. Both sides in the debate worked over the weekend to shore up their support.
A fragile compromise was forged in early June, but Senate leaders pulled the bill when passage appeared unlikely. It was resurrected after bipartisan negotiations with the White House, and this week's test vote is considered too close to call.
"We'll see if between the two parties we have 60 votes" needed to keep the bill moving toward a final vote, said Senator Dianne Feinstein, Democrat of California.
The measure would tighten borders, require workplace verification, and create a guest worker program. It also would lay out a way by which the estimated 12 million people illegally in the United States could gain legal status and work toward citizenship.
"I'm not committed to voting for the final product," Lott said yesterday on "Fox News Sunday." "The wheels may come off. But I am committed to trying."
Democrats have taken hits from their normal allies, including labor and some Hispanic groups. They say the proposal is bad for workers or that provisions for obtaining visas place too much emphasis on skills, to the disadvantage of family ties.
"We know what they're against. What are they for?" asked Senator Edward M. Kennedy, Democrat of Massachusetts. He noted that since the Sept. 11 attacks, there have been 39 hearings on immigration, 23 days of debate in the Senate, and 52 amendments.
"We have a terrible problem in this country that demands an answer," he said yesterday on ABC's "This Week."
But Senator Jeff Sessions, Republican of Alabama, a leading critic of the legislation, said support for the bill continues to plummet, both among senators thought to be behind it and among the public. "We are going to use every effort to slow this process down and continue to hold up the bill," he said on the ABC program.
NumbersUSA has mounted a campaign against the bill and any senator who supports it. The group will unveil TV ads against Senate minority leader Mitch McConnell, Republican of Kentucky, and Senator Lindsey Graham, Republican of North Carolina. Another ad will target Senate majority leader Harry Reid of Nevada.
Roy Beck, NumbersUSA president, expects to contact the group's activist members, who he says number 419,000. "We're in a war zone right now, so we're drawing down the reserves," he said.
Among those pushing the new immigration measure is President Bush, who appealed for support in his weekly radio address Saturday by stressing revisions to the bill that would require stepped-up enforcement before other provisions could take effect.
Most polls show that though Americans are concerned about border security, a majority favor finding a way to allow most immigrants now in the country illegally to gain legal status.
NumbersUSA says population growth is damaging the nation -- creating urban sprawl, snarling commuter roads, straining schools and hospitals, and diminishing natural resources. It says immigration propels much of this growth and should be restricted.
The United States issues about 1 million visas annually for legal permanent residency. The group wants that number to drop to the early 20th century level, about 250,000.
The Senate bill would not limit total numbers of legal immigration, and NumbersUSA doubts it would effectively stop illegal entries.
NumbersUSA members in Mississippi said they sent Lott about 10,000 faxes and letters since he began supporting the bill in early June. Lott said his phone lines were jammed with protests of the bill, most from outside his state.
"You have to give them credit: The phone calls, the faxes, the people who show up at town halls and meetings -- you have to say NumbersUSA is behind a fair amount of that," said Frank Sharry, director of the National Immigration Forum, a nonprofit group that advocates for immigrants.
Sharry acknowledged that NumbersUSA helped flip Georgia's two Republican senators, Johnny Isakson and Saxby Chambliss. The two, who helped write the immigration bill, were targeted by the group. Both have withdrawn their support .
"Why is Trent Lott, who is getting hammered with letters and faxes and talk radio, getting stronger in favor of the bill instead of weaker?" Sharry asked. "He knows that for all their bluster, there's no real threat."
Material from the Associated Press was included in this report.