Who decides if the "proof" is sufficient?
He's still looking for "approval" of other nations (which ones? Bad question. Don't ask.)
And of course, this also presumes that any potential opposition of other nations is based on rational reasons, as opposed to less-pure motives, like raking in billions from Iraq, support of cooperative thugocracies, or outright hostility to America no matter what it does.
I would bet money that if Saddam had had fifty nuclear missiles lined up in silos, only months from deployment, that France and a few other choice nations would still have opposed the invasion.