When the Gang of Eight filed its massive immigration reform bill, many observers predicted a long, momentous struggle before any legislation — probably changed in fundamental ways by an arduous amendment process — made it through the Senate.

Now, after a few days of on-and-off consideration of the bill, one well-connected Senate source concludes: “This thing’s over.”

As the source sees it, the Senate will vote on the still-unreleased Hoeven-Corker amendment on Monday.  And then, Majority Leader Harry Reid will move for a final vote. “We’ll vote on Corker, a couple of remaining pending amendments, and then cloture on the final bill as amended by Corker, and call it a day,” says the aide. By “call it a day,” the source means the Senate will pass the bill.

In all, it’s been a much shorter process than many predicted when the bill was first introduced, and shorter even than Reid predicted just three days ago when this week’s debate began. ‘I’m just telling everybody that we’re going to either file cloture on this on Friday or Saturday or Sunday or Monday,” Reid said as the Senate opened its morning session on June 18. “This may not be one of our normal weekends,” Reid added. “We’ve got to move forward on this legislation.”

As it turns out, the Senate will not be working on Saturday. It won’t be working on Sunday. It won’t even work very late on Friday.

The fact is, if Hoeven-Corker is actually finished — and sources say it will be, although it is behind schedule — the Senate fight is pretty much over. Much of the discussion of the bill has focused on whether the Gang of Eight can draw 70 votes for the bill or will be content to pass it with just 60 votes. That’s not much of a debate. The bill passes either way, most likely by next Thursday at the latest.

Then the bill moves on to the House, where it faces a troubled future. “In the end, it’s all moot,” says the Senate source. “While I expect it will pass here [the Senate], that will be the end of it. I don’t think the House will even take it up, much less pass it.”