This Hill article (via Tapped) is a nice summary of the current state of affairs around the defense bill. A major fight could be brewing, as Republicans consider a modified "nuclear option" and Dems consider a filibuster.

The issue is fraught with political risks for Democrats. A conference report cannot be amended. Because the House has already passed the measure, the conference itself has been vitiated and the report could not be recommitted. Thus, a successful point of order against the ANWR provision would kill the bill and force Republican leaders to create a new conference committee or pass an extension beyond the current Dec. 31 expiration to keep the Pentagon operating.

Under that scenario, or a successful filibuster, Democrats could leave themselves open to accusations of shutting down the Defense Department and denying money to American troops on the ground in Iraq.

What is the Republican defense for this grossly anti-democratic maneuver?

Republicans argued that Democrats had used similar means to achieve their ends when they held power.

Just like your grade school teacher taught you.