This section is from the book "The Constitutional Law Of The United States", by Westel Woodbury Willoughby. Also available from Amazon: Constitutional Law.
As the term indicates, a modus vivendi is a temporary arrangement entered into for the purpose of regulating a matter of conflicting interests, until a more definite and permanent arrangement can be obtained in treaty form. Continued and unquestioned practice supports the doctrine that these modi vivendi may be entered into by the President without consulting the Senate.10
 
Continue to: