The Catholic Church and politics concerns the interplay of Catholicism with religious, and later secular, politics. Historically, the Church opposed liberal ideas such as democracy, freedom of speech, and the separation of church and state under the grounds that "error has no rights" . Eventually accommodated these ideas and began to view religious liberty as a positive value during and after the Second Vatican Council. Background According to the United States Conference of Catholic Bishops, "the separation of church and state does not require division between belief and public action, between moral principles and political choices, but protects the right of believers and religious groups to practice their faith and act on their values in public life." 19th century As a program and a movement, political Catholicism – a political and cultural conception which promotes the ideas and social teaching of the Catholic Church in public life through government action – was started by Prussian Catholics in the second half of the 19th century. They were responding to the secular social measures of Chancellor Otto von Bismarck to limit the influence of Catholic Church, first in Prussia, and then in united Germany, a struggle known as the Kulturkampf. From Germany, political Catholic social movements spread in Austria-Hungary, especially in today's Austria, Ukraine, Slovenia and Croatia. Catholic Action was the name of many groups of lay Catholics attempting to encourage Catholic influence on political society. Political changes in Spain during the second half of the nineteenth century led to the development of Catholic Integrism and Carlism struggling against a separation of Church and State. The clearest expression of this struggle arose around the 1884 publication of the book Liberalism is a Sin by Roman Catholic priest Félix Sardà y Salvany. The book was rapidly referred to Rome, where it received a positive, albeit cautious welcome. Pope Leo XIII's 1891 encyclical Rerum novarum (Of New Things) gave political Catholic movements an impulse to develop and to spread the area of their involvement. With this encyclical, the Catholic Church expanded its interest in social, economic, political and cultural issues, and it called for a drastic conversion of Western society in the 19th century in the face of capitalist influences. Following the release of the document, the labour movement which had previously floundered began to flourish in Europe, and later in North America. Mary Harris Jones ("Mother Jones") and the National Catholic Welfare Council