The Irish Republic had some of the attributes of a functioning state; a ministry (with a head of state in the latter stages), a parliament, a courts system, a police force and a constitution. The extent to which these functioned fluctuated in different parts of the island, with the success or otherwise of republican institutions depending both on the degree of control of the IRA in the region and on the brutality of the Black and Tans and Auxiliaries, active from June 1920 to July 1921. The more brutal the 'Tans' the more they alienated the local populace from the Dublin Castle administration and Assize courts and the greater success the republican alternatives had. Some measures such as the Dáil Decree of 6 August 1920 prohibiting emigration without a permit were violently enforced.