Python 'if' statement not triggering correctly

For some reason, no matter what user_input is (Yes, No, "", eserw3) the first if statement will always be triggered. Any insight as to why the elif and the else never get activated? (The below code compiles perfectly without any errors)

Thank you in advance.

def retry():
        user_input = raw_input("Would you like to face %s again? (Yes/No)" % (Enemy))
        if user_input == "Yes" or "yes":
            respawn()
            getMove()
        elif user_input == "No" or "no":
            print "Thanks for playing!"
        else:
            print "Please enter either Yes or No."