Complex sentence: West Germany was to be permitted to rearm, an idea which was rejected by many Germans, and have full sovereign control of its military, called the Bundeswehr; the WEU would however regulate the size of the armed forces permitted to each of its member states.
Split into simpler sentences: West Germany was to be permitted to rearm (an idea many Germans rejected), and have full sovereign control of its military, called the Bundeswehr. The WEU, however, would regulate the size of the armed forces permitted to each of its member states.