Senate Democrats so far have said they will not return, and that the only way to get the payroll tax bill approved is for the House to pass the Senate's two-month extension. Until one side gives in, the default result will be no extension of the payroll tax holiday, unemployment insurance or the doc fix.

While this offstage showdown continues, the only onstage action to watch will be the pro formas. The House meets at 10 a.m. Wednesday and 10 a.m. Friday.

The Senate had a pro forma on Tuesday, and will meet again in similar fashion on Friday at 9:30 a.m.