The energetic Colonel Mohamed Khouna Ould Haidallah soon emerged as its strongman. By giving up all claims to Western Sahara, he found peace with the Polisario and improved relations with its main backer, Algeria. But relations with Morocco, the other party to the conflict, and its European ally France deteriorated. Instability continued, and Haidallah's ambitious reform attempts foundered. His regime was plagued by attempted coups and intrigue within the military establishment. It became increasingly contested due to his harsh and uncompromising measures against opponents; many dissidents were jailed, and some executed. In 1981 slavery was formally abolished by law, making Mauritania the last country in the world to do so.