Sentence:  The action of the Commission in allowing or denying any claim under this title shall be final and conclusive on all questions of law and fact and not subject to review by the Secretary of State or any other official , department , agency , or <WSD>establishment</WSD> of the United States or by any court by mandamus or otherwise . 
Meaning of the word marked with <WSD> tags:  the persons (or committees or departments etc.) who make up a body for the purpose of administering something