digging in

Philip Bump at the Washington Post reported that the House is digging in its heels on their part of the recess appointment gambit as well:

As the conference approached its scheduled end this week, the U.N.’s climate chief chided negotiators for digging in their heels and wasting time with bluffing and brinkmanship.

But he kept digging and digging in the hopes, Kimmel says, of trying to get under the skin of the oft-inscrutable Carson.

The hosts were caught between hitting themselves out of trouble and digging in.

So while it's not surprising Robinson is digging in and refusing to drop out, it's a little more surprising that he's chickened out, unwilling to own his past posts.