The Fast and Furious investigation can not stop with the resignation of Kenneth Melson, acting director of the ATF. We already know that other Federal agencies including DEA, ICE and Border Patrol were involved in Operation Fast and Furious. None of those agencies report to Kenneth Melson. Authorization for the involvement of those other agencies had to come from higher up. Both BATFE and DEA report to Eric Holder and since the operation crossed his agencies, he was involved. Similarly, Border Patrol and ICE report to Janet Napolitano and since the operation crossed her agencies, she was involved. Since the operation crossed departments (Homeland Security and Justice) and those departments report to Obama, he too had to have been involved — it can really be NO other way.
That would put Hillary in the loop as well.