Yesterday, a GOP aide, who is one of my sources in the Senate, gave me the rundown on what's currently happening with the Senate immigration bill (You can see my two previous reports from this source here and here).

To begin with, the key thing to keep in mind about the upcoming vote on the Senate immigration bill is that the pro-amnesty forces have two key cloture votes that they have to win.

The first is the vote on the so-called "clay pigeon" strategy. What this does is take the original bill and all of its amendments and reintroduce it on the Senate floor as a new bill. There are two reasons for doing this. The first is to prevent killer amendments that could upset the "grand compromise" from being voted on. The second reason is procedural, because it keeps conservative senators who are opposed to the bill from being able to slow up the process.

However, in order for the bill and the previous amendments to be offered on the floor of the Senate as a new bill, it will take the cooperation of both Democratic and Republican leadership, along with 60 votes for cloture.

The conventional wisdom has been that this first cloture vote is a done deal because the Senate leadership has been wheeling and dealing behind the scenes. The way it works is that they go to a senator and offer to allow a vote on their Amendment IF -- and only if -- that senator agrees to vote for cloture on the "clay pigeon" strategy.

My source tells me that this has left a sour taste in the mouth of a number of Republican senators who are upset that Mitch McConnell is cooperating with Harry Reid to curtail the rights of Republican senators. Moreover, there's a growing fear that a dangerous precedent is being set here that could be used against Republican senators again and again as long as they're in the minority. After all, if the "clay pigeon" strategy is used against conservatives on the immigration issue, who's to say it won't also be used against them on any number of issues in the future? According to my source, this is causing a lot of nervousness amongst Republican senators and it has Mitch McConnell acting very defensively behind closed doors about working with Harry Reid to roll members of his own caucus. Because of this issue, my source tells me that the vote for the "clay pigeon" strategy is no longer a slam dunk and it is possible that the "grand bargainers" may not be able to get 60 votes to put the bill on the floor as a new bill. If that turns out to be the case, the bill is dead.

Then, if the bill does make it to the floor, there will be 30 hours of debate, and then a second cloture vote. Of course, if Senators voted for the fist cloture vote, there wouldn't seem to be any logical reason to then turn around and vote against the second cloture vote although for opponents of amnesty, that will be the last real chance to kill the bill.

If the bill makes it through the second cloture vote, 22 amendments will be offered. These amendments have been carefully selected by the combined Democratic/Republican leadership to try to make sure that no deal breakers can make it through. If certain amendments pass, it could cost votes. On the other hand, some senators may very well decide not to vote for the bill if their amendments don't pass. But, once the votes on the amendments are through, there will be another final vote for passage, but this time, only 50 will be needed and the bill would be almost certain to be approved if it gets this far.

Summary: My source tells me that he thought the amnesty proponents definitely had the upper hand last week, but now, he thinks the momentum may be swinging back the other way. He also said that he thinks the best chance to stop the bill will be on the initial cloture vote. He said that he's hoping that a coalition of conservatives who think this is a bad bill, liberals who think this bill is too tough, and Republican senators worried about losing minority rights because of the "clay pigeon" strategy will get together and block the bill.

PS #1: I pointed out that John Edwards and Claire McCaskill have made some extremely negative comments about the bill and asked my source if it's possible that Democratic opposition could increase enough to kill the bill. He said it was possible, but he thought Harry Reid was capable of strong arming the Democrats enough to keep them from losing many votes. Of course, he also added that he's not sure that Harry Reid really wants to see this bill pass, so he's not sure how hard he would fight for it. Either way, he said not to count on the Democrats to finish off the bill.

PS #2: I asked him about Johnny Isakson and Saxby Chambliss announcing that they will vote against cloture. My source's take was that it wasn't a bill killer, but that it was significant since both of them were prominent early supporters of the bill. He added that he thought their switch was indicative of the pressure Republicans are feeling at the grass roots level and he said that he thought Isakson and Chambliss deserved credit for paying attention to it while a lot of pro-amnesty supporters have tuned it out or even shut off their answering machines because they're tired of hearing their constituents complain about this issue.

PS #3: Last but not least, I talked to my source about the shots Trent Lott and Lindsey Graham have taken at people opposed to the bill. My source replied that when this whole thing started, these guys were cocky and thought they'd get this bill through with 70 votes, no problem. But now, because of the blogs and talk radio, they've lost the public debate on the issue and they know it. So, at this point, they're way out on a limb supporting a wildly unpopular bill that may or may not pass, and they're lashing out in frustration. He added that a lot of Republican senators have been offended and embarrassed by their comments and are worried that the voters will lump them in with Graham and Lott.

Update #1: My source conferenced with some other people he works with and called me back this morning to clarify how the clay pigeon strategy works: there will be two cloture votes, but the 2nd cloture vote will take place BEFORE the Amendments are voted on.

In other words, there will be a cloture on Tuesday, then there will be 30 hours of debate, and then there will be a second cloture vote. If the 2nd cloture vote passes, the amendments will then be voted on, and then we'll have the final vote on the bill.

So technically, a senator could vote for the cloture the first time and then change his/her mind and vote against cloture the second time, but that would seem to be unlikely, because the amendments won't have been put to a vote.

The original article has been edited to reflect this.

PS #4: This clay pigeon strategy is so rarely used that there is a lot of contradictory information out there about how it works. For example, Richard Burr seems to be indicating that there WILL BE amendments offered between the cloture votes,

"Republicans outside the negotiating team are asking that Graham's amendment, as well as a few others, get a floor vote before a cloture is attempted on the bill. "If they want the bill to have a chance, that's what has to happen," said Sen. Richard Burr, R-N.C., who said he is willing to vote for the first cloture motion to proceed to the bill to allow the amendment process to begin.

Burr left open the possibility he would vote for the second cloture motion, which would ensure a final vote on the bill, if the bill is improved from his perspective by the amendments."

However, my source is telling me that will not be the case.

Update #2: Here's diehard amnesty supporter, Jon Kyl on the 2nd cloture vote,

"I think that perhaps on Tuesday, the cloture vote to take the bill back up again will be voted on and will pass. It'll be fairly close. There will then be votes on amendments, and there are some key amendments that need to pass, many of the ones that we talked about here tonight. There are others that need to be defeated. There will then be a cloture vote on finishing the bill, and some of the amendments will be voted on after that cloture vote. So it's not going to shut off debate and amendments. But it will result in 30 additional hours, and then the bill coming to a close. And my guess is at the end of the day, there will be more votes for final passage even than there are for cloture."

According to Kyl some of the amendments will be voted on before the 2nd cloture vote and some of them won't. So again, people are all over the map on this issue.