Sentence:  States were free to enact , within broad though ( perhaps ) determinate limits , their own rules as to the application of foreign law by their courts , to <WSD>vary</WSD> the law merchant , and to enact legislation with regard to many claims arising on the high seas . 
Meaning of the word marked with <WSD> tags:  become different in some particular way, without permanently losing one's or its former characteristics or essence