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 <WSD>official</WSD> , department , agency , or establishment of the United States or by any court by mandamus or otherwise . 
Meaning of the word marked with <WSD> tags:  a worker who holds or is invested with an office