There was a question hanging in the air as Republican senators met privately at midday Tuesday to discuss the divisive fight over defunding Obamacare: How did this get to be about us?

With all the "train wreck" problems of Obamacare coming into view just days before the health plan's exchanges are scheduled to go on line -- rising costs, lost jobs, reduced hours, and more -- how did Washington become entangled not in those issues, which will affect millions of people, but in an insider drama among a few Republicans who all agree Obamacare should go but disagree on the best tactics to fight it?

Tuesday was the day it became unavoidably clear to Sens. Ted Cruz and Mike Lee, the leaders of the defunding-by-filibuster fight, that their effort will fail for lack of Republican support. Cruz and Lee had asked their fellow Republicans to filibuster the House-passed continuing resolution that defunds Obamacare so that Majority Leader Harry Reid and Democrats would not be able to strip out the health law provision. Of course, that was the very continuing resolution Cruz and Lee had asked the House to pass. By Tuesday, their filibuster-the-bill-to-save-it strategy was too convoluted for Senate Republican colleagues to accept.

"Well, look, I think we'd all be hard-pressed to explain why we were opposed to a bill we were in favor of," Senate Minority Leader Mitch McConnell said after Republicans held not one but two meetings about the issue. Voting to move the resolution forward -- precisely the move Cruz and Lee are trying to avoid -- "strikes me as a no-brainer," McConnell said.

So much for that plan. After McConnell and number-two Republican John Cornyn came out against the Cruz-Lee plan Monday, a long line of Republican senators -- Coburn, Hatch, Blunt, Chambliss, Johanns, McCain, Coats, Barrasso, Boozman, Corker, Burr, Shelby, Alexander, and others -- joined them. So there was no longer any question that the continuing resolution would go forward.

At that point, in the private meetings, GOP senators began talking about a new idea. Since the Cruz-Lee filibuster was definitely not going to succeed, why go through the time-consuming motions of doing it at all? Under the current schedule, there will be an initial cloture vote on Wednesday, then another on Saturday. Then Reid will introduce a measure to strike the Obamacare defunding provision, which the Senate will pass over the weekend. Then there will be a final bill on the "clean" continuing resolution, which will pass and be sent to the House. The only problem is, at the point the House will have less than 48 hours to decide what to do before the government runs out of money and a possible shutdown begins.

So a number of Republicans began talking about speeding things up. Why take all week with cloture votes when the result is already known and the shutdown clock is ticking? Why not finish the resolution now and give the House some actual time to do its work?

That was certainly McConnell's view. "I don't know who else in the conference may feel differently," he said Tuesday, "but I do know that if the House doesn't get what we send over there until Monday, they're in a pretty tough spot. My own view is, the House having passed a bill that I really like and intend to support, I hate to put them in a tough spot."

As the senators discussed the matter, there was significant support, perhaps majority support, for the speed-up scenario. But even majority support is not enough; to change the agreed-upon schedule requires unanimous consent, meaning even one senator can stop the plan by objecting. And the leaders of the defunding effort did not agree. So even if Democrats were amenable to the idea -- which is unclear -- the fact is, Republicans couldn't agree unanimously among themselves. So the schedule remains the same, and the House will be under tremendous pressure when the measure comes to them at the beginning of next week.

That is precisely the scenario McConnell had hoped to avoid. But Cruz, Lee, and their supporters did not budge. So the Senate debate will go on.

After the Republican meetings, Cruz and Lee went to the Senate floor to begin a talkathon on defunding. (It wasn't officially a filibuster because the agreement stipulates the first cloture vote will come one hour after the Senate convenes on Wednesday; Cruz and Lee cannot change that, no matter how long they might want to talk.) For the first hour, the two were the only senators on the floor. Cruz spoke only to a C-SPAN camera, while Lee studied his notes and prepared to join the discussion.

And then something unexpected happened. Sen. Jeff Sessions, who had been uncommitted in the matter, came to the floor to announce that he will vote with Cruz and Lee. Back in July, when Lee circulated a letter asking his fellow senators to pledge not to support any spending measure that funded Obamacare, Sessions declined to sign. But now Sessions was on board, the first senator who hadn't signed the letter to join the cause. "I intend to support you," Sessions told Cruz, "and I'm not going to vote to move a bill where we are sure we're going to be blocked from having any meaningful discussion of one of the most historic, damaging bills in maybe the last 100 years…"

Just a month ago, Sessions expressed deep doubts about the tactic. "I'm not sure it’s the best viable way at this point," he said on Bill Bennett's radio show in August. "I've looked at it really hard, I’ve talked to Mike, and I certainly respect what he's doing, but I’m not convinced right now that this is going to be a way that will be successful and effective." By Tuesday, Sessions had become convinced, even though he took care to express respect for colleagues who sided with leadership. "I didn't sign the letter, and I've got some great friends who see it differently than I do," Sessions said. "Good people, I think, can disagree on this."

Sessions might not be alone. Speaking privately late Tuesday afternoon, a Republican senator suggested more lawmakers might soon join Cruz and Lee. They would not do so if it meant the filibuster would succeed and the government might shut down, but now that enough Republicans have made their positions known and shutdown is off the table, they will join the defund-by-filibuster effort. The reason, the GOP senator suggested, is that the outside groups pushing the defunding gambit -- Heritage Action, Senate Conservatives Fund, FreedomWorks -- are actively pressuring lawmakers to go along. Now that it's a sure bet the continuing resolution will not be stopped, some Republicans might choose to seek safety from the groups' wrath by joining Cruz and Lee. The perverse result could be that the Senate Republican caucus will appear more divided than it actually is.

That is just the opposite of what McConnell and the GOP leadership hoped would happen. There's no doubt Republicans are united in opposing Obamacare. Why can't they be spending this week forcing Democrats to defend the troubled health plan? Instead, the GOP's high-profile differences over strategy have taken center stage, and Republicans can't seem to do anything about it.