We actually have to choose his worst foreign policy mistake? Has he done ANYTHING right? ANYTHING??
You're right, how do you rate/rank so many serious problems? It's like looking at a house leveled by a tornado and trying to decide if the broken windows or ripped off shingles are worse. (ok, the analogy cops may come after me for that one)
I wouldn't sign any deal with the Russians. The FBI just nabbed what, 50 or so Russian spies in our Country? I'd tell them all treaties, all agreements in the works, everything is on hold while we "re-evaluate our relationship."
Remember back when giving the Queen some crappy DVDs seemed like the dumbest thing he could do?