Terms for subject Formal containing по закону

Russian	English
обязанный по закону	legally required (Here in Vancouver, we are legally required to tweet about it when it snows. So on advice of counsel, here is my submission in accordance with said legal requirement. (Twitter) ART Vancouver)
по закону не обязан	there is no legal obligation (for sb. to do sth.: [Justice David] Crerar conceded it may have been prudent for the trustee to apply to have the deposits sent to the courts, but he found there was no legal obligation for him to do so. nsnews.com ART Vancouver)