Many Catholics do not know that canon law allows their bishop to impose taxes on the parishes in his diocese for diocesan needs. Under canon law, these diocesan taxes, sometimes called diocesan assessments, parish assessments, or quotas, must be proportionate to [the parishes'] income. To a tax lawyer, the adjective proportionate describes a so-called flat tax, or a system that imposes the same tax rate on every taxpayer's taxable income. Canon law commentators, however, have consistently agreed that diocesan bishops can use a progressive tax, which in this context would impose a higher tax rate on parishes with larger incomes. This article argues that Catholic social teaching, including the U.S. Bishops' 1986 pastoral letter on the U.S. economy, should persuade the diocesan bishops in the United States to use progressive rates whenever they impose diocesan taxes and assessments under canon law. 

An early 2003 survey underlying this article gathered data from eighty-five of the 176 geographic dioceses in the United States. The survey results reveal that those bishops who impose diocesan taxes or assessments used flat tax rates almost four times more frequently than progressive rates. Given the survey's findings and Catholic social teaching on distributive justice, this article recommends a review of diocesan tax and assessment policies and practices across the United States. Where necessary or appropriate, the article respectfully urges certain changes in those policies and practices, especially the conversion to progressive tax rates. In essence, the bishops should practice what the Gospel, the universal Church, and they themselves teach.