A letter to the editor to the paper of the Diocese of Savannah sums up nicely the difference between charitable giving (a free act) and taxation for charitable purposes (a compelled act). Deacon Thomas Eden of Saint Joseph Church in Macon, Georgia asserts that we are spiritually called to see the "person of our Lord Jesus Christ in the sick, poor, disabled and hungry we encounter and act accordingly." However, we are not urged anywhere in scripture to shift this obligation onto the government, thus allowing them to choose whom to help. Deacon Eden writes "We are held accountable for our personal social action, and cannot escape it by selective community socialism that removes us from the participation of serving our brothers, with our time, talent and money. "
For examples of the effect of the replacement of donation with taxation, he looks to Europe and Scandanavia, which have "formed a tax structure that puts government n the position of choosing those groups of people and charities that get support." The countries with these policies have seen a marked decline in Christian and Catholic participation.
Check out the whole letter here on page 3.