Only caveat: The CIA is essentially a terrorist organization. Will get hated, but essentially it causes whatever strife it has to in order to further the goals of the United States, committing more and more evil acts for it. If the CIA exists in the UN and its focus has shifted to humanity rather than the US, then the UN will soon be seen like the US is seen on our Earth - as a cartoonishly evil state that is funding terrorist organizations and then acts confused when evil methods backfire.

The CIA would be the type to make the Arxur even more evil and strong to wipe out the Feds, and then act surprised when said Arxur attack the UN, considering them weak.