In his January 7th address to the members of the diplomatic corps accredited to the Holy See, Pope Benedict XVI said that “the increasing differences between those few who grow ever richer and the many who grow hopelessly poorer, should be a cause for dismay.”  The Pope didn’t add anything to Catholic doctrine with this statement. The Catechism of the Catholic Church mentions the “sinful inequalities that affect millions of men and women,”  and declares that these “are in open contradiction of the Gospel….” The Catechism goes on to say this:
“Their equal dignity as persons demands that we strive for fairer and more humane conditions. Excessive economic and social disparity between individuals and peoples of the one human race is a source of scandal and militates against social justice, equity, human dignity, as well as social and international peace.”
The teaching about income inequality is not a dispensable part of Catholic social doctrine. Unjust economic inequality being “in open contradiction of the Gospel,” Catholics ought to be alerted that the situation commands the highest level of attention. Unfortunately, the political lines that have been drawn in the United States have caused some to shun the importance of the issue, thereby ceding it to forces unfriendly to the Church and her mission.
What to do about income inequality is, of course, a further question to be explored. It should be pointed out that those who would decry as unjust income redistribution through taxation will not find support in Catholic social teaching which, while it upholds the right to private property, also holds that the “goods of creation are destined for the whole human race,”  that political “authority has the right and duty to regulate the legitimate exercise of the right to ownership for the sake of the common good,” and that the “the appropriation of property is legitimate for guaranteeing the freedom and dignity of persons and for helping each of them to meet his basic needs and the needs of those in his charge.”
Still, most people hope for better for themselves than being welfare recipients. While there is no excuse to be found in the fact that receiving welfare is not the optimum goal of human life for the failure of a society to provide it where it is needed, there can be no doubt that conditions where people support themselves through their own work are more conducive to human flourishing. That is why society has an obligation to “help citizens find work and employment.” 
But employment ought to eliminate the need for welfare for the person employed. That only happens, however, if the wage is adequate for the employee to support himself or his family. If the wage is not adequate an injustice is being perpetrated. As the Catechism says:
“A just wage is the legitimate fruit of work. To refuse or withhold it can be a grave injustice. In determining fair pay both the needs and the contributions of each person must be taken into account. ‘Remuneration for work should guarantee man the opportunity to provide a dignified livelihood for himself and his family on the material, social, cultural and spiritual level, taking into account the role and the productivity of each, the state of the business, and the common good.’ Agreement between the parties is not sufficient to justify morally the amount to be received in wages.” 
Calculation of the proper wage meeting this standard entails some complication to be sure, and will vary from place to place. The United States Department of Health and Human Services’s poverty guidelines sets the poverty line for the year 2012 at $23,050.00 for a family of four.  If unpaid sick days and holidays are disregarded, that works out to $11.08 per hour. But the federal minimum wage is $7.25 per hour , insufficient to bring a family of four even up to the poverty line.
There are those who will say that raising the minimum wage to a wage sufficient to support a family will reduce the number of jobs that employers will be able to provide, and will, therefore, increase unemployment. Indeed, some advocate for the abolition of the minimum wage, arguing that unemployment will decrease as a result.
But the general well-being of a society cannot be enhanced by the presence of workers consigned to poverty even though they are employed. It will either result in social blights such as wide-spread malnutrition, or it will require the rest of society to make up the difference between the wages of such workers and what is required to have their needs met. What’s more, if social services are not forthcoming for those who are unable to support themselves and their families by means of their wages, there will be an incentive for those so afflicted to supplement their income through criminal activity. There is little rationality in the expectation that people will passively starve where they are surrounded by abundance possessed by others.
Tax incentives could be a solution to counteract the increase of unemployment that might be otherwise occasioned by the increase in minimum wages. Businesses that pay workers living wages are providing a public service that should be rewarded. Those who pay poverty wages, thereby rendering their employees public charges, are harming society, and should receive no tax benefits at all.
Income disparity becomes unrighteous when those at the bottom level of income are unable, by their income, to provide for their basic needs with dignity. Every legitimate vision for social reform should include the rectification of this inequity in American society.