You know what seems odd to me is the fact that the Federal Government is trying to act like their in charge of the Guard. It tells the Guard what it can and cannot do. The President acts or at least the media gives people the impression that the President is "ordering" the Guard to the border when he is really only recommending to the governors to use their own state militias. The States need no permission from the federal government to use their own National Guard forces when the Guard is not actively called into the service of the Federal Government yet the Senate tries to make a power grab/good soundbyte by passing an amendment authorizing the border states to use the Guard and telling the guard what it can and cannot do. If the Senate wants to act like its in charge of the Guard it can follow the Constitutional rules and federalize the guard by calling it into the ACTIVE service of the Union then they can set the rules and the President can command them. Until then the states call the ALL of the shots with respect to what the Guard does.
Except that the Feds are likely funding this call up of the Guard. Therefore, the Senate is authorizing money for this purpose.