I think that the arrival of aliens with interstellar reach would be the thing to motivate them in that direction. Even Putin’s fundament would be very tightly clenched, if he’s a sane man.
Real men make their own cookies.
OK. Do you taste bad?
Brussels? Really? Not London? Or Berlin, Paris, or Tokyo?
Brussels is the de facto capital of the EU. But I’m not sure it’s more important than London or Paris; when the shit hits the fan those countries will be acting in their own best interests, not in that of the EU.
The correct answer is Jodie Foster.
↑ ↑ ↑ Bingo… 
Wait, I thought it was James Cromwell. It would only be logical.
Brussels has a direct line to Frau Merkel.
I have to wonder if its worth an alien races time to contact us.
The Doctor.
He’d step in and sort it all out before anyone else had figured out what was going on.
The UN in a pinch, spearheaded by the Secretary-General. With a bit more time to spare (like we have a few months to prepare after detecting a space borne fleet), some representative off shoot of the UN should be created specifically designed for the purpose. I must say that one country doing this alone is absolutely the worst possible option. In a list of the best-worst possible option, I think America is about 12th, far behind the top spot. Switzerland should be the first to have a crack if the UN happened to be asleep or drunk at the time.
The person who would speak for mankind is a woman called Simonetta Di Pippo who is the director of (not making this up) United Nations Office for Outer Space Affairs.
This question actually has a factual answer. So eh, should be moved to GQ?
Not a human, we’ve lost that right.
I think a cetacean or a pachyderm.
What? Aliens wouldn’t understand them? How would aliens understand us?
By whose standards have we lost the right? What moral laws do you say we’ve violated?
Clearly, this is the sort of thing that can only be determined by a single-elimination basketball tournament.
Fortunately we’ve got time, as the aliens are still arguing over who to send.
What you really mean is that we should send Dick Vitale, right?
That’ll do Pig, that’ll do.
The factual answer is that if aliens land and announce “Take us to your planetary leader, puny hu-mons!”, we’d have to answer “Our planet does not have a single leader.” Just like if aliens landed in New York and demanded to be taken to the King of America, we’d have to tell them we don’t have a king. We could tell them that we have a president, who’s sort of like a king, but if they demanded to see a king and nothing but a king we’d be out of luck. Also, if they demanded to be taken to Batman, we’d have to tell them Batman doesn’t exist, and if they demanded to be taken to our X’zzy-ptang!rkkkk, we’d have to tell them we have no idea what a X’zzy-ptang!rkkkk is.