If you are barking about an action Truman did, and no one made any objection...then it's probably a battle you are not going to win, even if you are right. It seems the Director of the CIA had a good idea, sent it to the Deputy NSC, and then it went to Truman. I'd have to dig into the archives to see what deal was made for funding, but it could not have been implemented without some acknowledgment from Congress that it need to be secret, and it needed to be built.
You’ve been in D.C. so long that you can’t see the forest for the trees. The Administrative or Regulatory State are a huge collection of agencies that “regulate” (ie. make law apart from Congress, the ONLY lawmaking branch the Constitution allows) that are basically unaccountable to the people of the United States because they do not directly report to any of the three accountable constitutional branches.
http://thf_media.s3.amazonaws.com/2012/pdf/sr116.pdf