A bipartisan immigration reform package is in danger of becoming the highest-profile victim of the ongoing Congressional stalemate over Iraq and the heightened political tensions that have gripped the narrowly divided Senate this year.

Though no one is ready to write off passage of a compromise immigration bill just yet, the stakes increased Tuesday when Senate Republicans said they may try to trip up the Democrats’ plans to begin debating the issue next week. And, as a counter, Democrats reiterated their threat to force Republicans to take another vote on last year’s bill — one that garnered more than 20 GOP supporters.

Republicans and Democrats alike say they hope immigration reform still can find its day in the Senate, especially after months of bipartisan talks that involved the White House and lawmakers of every political stripe. Still, they acknowledged that, along with the simmering Iraq debate, immigration reform remains one of the most delicate topics facing the 110th Congress.

“We’re at a very sensitive point in all of this,” said Sen. John Cornyn (R-Texas).

“The bottom line is we’re committed as long as the White House is willing to move in a direction that is reasonable,” added Sen. Bob Menendez (D-N.J.). “Time is marching on us. There have been some hard decisions. We’ve come a long way.”

Both Cornyn and Menendez are among a group of about 10 Senators who have been meeting with key White House officials for several weeks to try to craft an immigration package that is palatable to a broad consensus in the Senate. And while those talks are continuing, the fragility of the discussions increased Tuesday when Republicans suggested they might block Majority Leader Harry Reid (D-Nev.) from moving to the immigration debate next week on a placeholder bill before the talks bear fruit.

Senate Minority Whip Trent Lott (R-Miss.) said he hopes a GOP filibuster is “not necessary” next week and that “both sides can still come together and produce a bill.”

“But we’re not there yet,” Lott said. “We’re not ready to go to the floor” with a deal.

Even so, Reid isn’t backing down, and he said Republicans have known for some time that immigration would occupy the Senate’s calendar the last two weeks of May. The Majority Leader added that if a consensus package produced in the meantime, it could be offered as an amendment to the “working document” making its way on the floor.

“We’ve got to address it,” Reid said. “Anyone who thinks two months [notice] is not enough time to get ready should get another occupation.”

The Majority Leader has not said what that working document would be, but Democratic sources said Reid may be inclined to bring up the previous session’s bipartisan Senate immigration bill that passed with more than 60 votes. That measure garnered more than 20 GOP votes and if brought up again could put Republican Senators in the difficult spot of explaining to voters their change of view on the issue.

“I can assure you that Sen. Reid is committed to taking a bill to the floor,” insisted one Democratic aide.

Meanwhile, Republican Senators are looking to hold a special conference meeting later this week to gauge their Members’ views and determine their strategy on the issue. GOP Senators may try to force Reid to bring up a separate placeholder bill — described as a “shell document” that never has been vetted previously by the Senate — to serve as the vehicle for the two-week debate.

Sen. Mel Martinez (R-Fla.), who sponsored the original bipartisan bill that cleared in the previous Congress, said that while he remains committed to reaching a deal, he isn’t interested in revisiting the past. And while he believes time is of the essence, he doesn’t believe it makes sense to try to have a debate before a deal on the legislation is brokered.

“We need to know where we are going before we get to the substance of a bill — that’s Senate 101, right?” he said.

Sen. Ken Salazar (D-Colo.) agreed the bipartisan talks must go on but insisted that in one way or the other the Senate must move toward considering the issue next week. If Republicans sought to block debate, it “would be an abdication of our duty to the national security of our country. This is something that needs to be dealt with.”

“It would be wrongheaded” to filibuster, Salazar said.

The White House continues to play a role in the talks, and another closed-door meeting is expected to take place today. One Bush administration official said that given the sensitive nature of the issue, they continue to approach it with kid gloves.

“It’s a 24-hour game,” said the White House official. “We take it day by day.”

Emily Pierce contributed to this report.