Senate Democratic leader Chuck Schumer say his conference won’t play the game of offering amendments to mystery health-care bills Republicans won’t disclose. Photo: Justin Sullivan/Getty Images

After the early drama of yesterday’s narrow passage of a motion to proceed, and last night and this afternoon’s decisive defeats of the two main GOP bills to repeal and replace or just repeal Obamacare, the U.S. Senate was settling down to a relentlessly boring series of floor speeches followed by mostly symbolic votes on a vast array of amendments.

Then this evening, Democratic Senate leader Chuck Schumer called BS on the whole process. And nobody quite knows why.

Alluding to widespread reports that Mitch McConnell plans to end the Senate health-care debate with a substitute amendment that will sweep away all previous legislation, Schumer announced that Democrats would not offer any amendments until such time as the GOP leader reveals the bill they are really debating.

Republicans almost immediately adjourned the Senate, with about eight hours of the twenty hours of debate guaranteed by the budget process remaining.

The Kabuki theater got underway today with party-line votes rejecting two Democratic motions to recommit the bill to Senate committees. But after that, Senate Democrats appeared to want to cut to the chase.

The Democratic boycott on offering amendments will probably shorten the “vote-a-rama” that was expected to keep the Senate up all night on Thursday, and perhaps heighten the pressure on Mitch McConnell, who has to figure out his endgame. In anticipation of the high probability that the final bill is some variation on the “skinny repeal” idea that’s seized Washington over the last 24 hours, Democrats managed to secure a confirmation of the Congressional Budget Office’s earlier estimate that repealing Obamacare’s individual mandate would cost about 16 million Americans their health coverage, while massively increasing individual health-care premiums.

It’s unclear tonight whether McConnell will pocket the time Democrats are conceding and move ahead like the legislative shark he often appears to be, or will instead feel compelled to abandon his habit of secrecy and tactical flexibility and come clean on what he will eventually ask his senators to support. Either way, you can understand Schumer’s reluctance to play the phony game of debating and trying to amend bills the GOP has long abandoned.