Both you are right. I have read that the proposed code shares was an attempt to scuttle the code share programs of US/UAS.
Now that that is a fact, they may still go ahead with it so that they can become much more dominant in Transaltlantic service and in Europe. The alliance would certainly be strenthened over there with the addition of KLM, and remember that SWISS is to join OneWorld and it already has Iberia, Finn and BA, and Star has Luft has SAS, so I don't see any problems with that.
Finally, the Republicans have no love for the unions but do know that customers do vote, so any large anti-monopoly effects should be precluded since this same Justice Dept viewed a US/UA code shares into and out of DC to be one.
Of course, the customers that those airports serve are not your regular joes and janes ...Congressional reps and lobbyists!