Mike Vanderboegh at Sipsey Street Irregulars has a very interesting post on the Traver nomination being sent back to the White House. Rumor has it that the Traver nomination was sent back with the full approval of notorious anti-gunner Senator Chuck Schumer.
The Chief Counsel's Office at ATF has a reputation for being a nest of vipers. That comes from both ATF agents in the field and pro-gun advocates. They also have good relations with Schumer and have been at his beck and call for years.
The rumor is that Andrew Traver wanted the Chief Counsel's Office cleaned out before he arrived so he wouldn't have to do it. Because of that the CCO worked with Schumer to have the nomination killed or at least stalled.
Remember this is all rumor and conjecture on Mike's part but he was the first one to call the Traver nomination. It was Mike's first post on Traver that got me to doing Google searches on the guy. Read his whole post linked above in the first paragraph.