Sentence:  Through trade and travel across the seas the American Merchant Marine is carrying out its historic mission of linking the United States of America with friendly nations across the seas ; And now , therefore , do I , John A. Notte , Jr. , Governor of the State of Rhode Island and Providence Plantations , proclaim Monday , May 22 nd , 1961 , as National Maritime Day , reminding our citizens that American Merchant ships and American seamen are ready at all times to <WSD>serve</WSD> our Nation in the cause of freedom and justice . 
Meaning of the word marked with <WSD> tags:  devote (part of) one's life or efforts to, as of countries, institutions, or ideas