I've always had a bit of grudging admiration for Richard M. Nixon, who despite his many character flaws, was a very perceptive guy. This fact becomes most apparent when you listen to him talk, either on his "self-bugged" White House tapes, or in interviews many years after he left the Oval Office in ignominy.
During once such occurrence, Nixon complained about someone's interference in the Vietnam-era Paris Peace Talks. He referred to the unnecessary intrusion as a "seagull mission".
In plain terms, or as John Sidney McCain might say, "straight talk", a seagull mission is when somebody swoops in on an ongoing process, makes a lot of noise, shits on everyone and everything, then swoops out again. This is absolutely what McCain did with the delicate economic negotiations yesterday. Before he came in and messed everything up, both parties had a tentative agreement in place. Afterward, the Republicans changed their proposal, added a bunch of ridiculous demands, and then absolutely refused to negotiate further.
I couldn't find the exact quote Nixon used, but here's an example of a "seagull mission" is available from an online document about a Canadian hearing (Pg. 5 Col. 1):
Years ago I did a fair amount of work on security services, and especially on their accountability. One of the terms used in security services is a seagull mission, where a spy or an agent flies into an area, makes a mess all over the place, then flies out again. I have a sense that quite often deputy ministers are on seagull missions in departments. They fly in, make a mess of things, and then fly out after a year.Mission accomplished Sen. McCain. That's some great leadership you're showing there.