The US/UAL merger was "blocked" -- never actually went to court, they withdrew from the deal under Bush. DAL/NWA was allowed under Bush. UAL/CAL was allowed under Obama. I would venture that the reason US/UAL was blocked while the UAL/CAL (a bigger merger) was allowed is that the condition of the economy and market had changed. Proof that the DOJ is a very poor prognosticator of the future. I would doubt any new president would get things back on track with regard to consolidation if this merger is blocked. (Not that I am not looking forward to having a new president, I am).