The traditional appeal of the income tax has come from its wide acceptance, as a fair tax, closely related to an individual's ability to pay. For many years the income tax provided large federal income without imposing heavy burdens on the great majority of people. By the mid-20m century, however, serious criticisms of tax loopholes were heard. Concerted attempts at reform. resulted only in a more complex and eroded tax base. The situation worsened in the 1970s, as rising inflation pushed people into higher tax brackets although their incomes were barely keeping pace with rising prices. This pressure further eroded public confidence in the fairness of the income tax at the same time it created strong incentives to utilize tax shelters and other loopholes, as well as to conceal off-the-record income. Built-in inflation adjustments were adopted, first by a number of states and then in 1985 by the federal government. Income tax policy is inevitably controversial because it rests essentially on judgments that must be constantly reconsidered as social values changes. The complex task of working out the many reductions and exclusions to be allowed from income because they either make for greater fairness among taxpayers or promote worthy social goals (such as charitable contributions) is one of the most difficult and politically sensitive problems faced by governments. Another major area of dispute is whether wages and salaries should be taxed the same way as business profits or investment income. While some countries and a few U.S. states explicitly apply separate stets of roles to the measurement of different kinds of taxable income, others, like most U.S. state governments, seek to treat all sources of income in the same way. Even so, dissimilarities inevitably arise. Some costs of earning income are mom readily deducted(扣除) from business and self-employment earnings than they are from wages and salaries. Inflation, by eroding the value of capital, distorts the measurement of income from that source. Complex adjustments to the tax law could in principle eliminate these imbalance, but most countries have preferred simpler, more arbitrary solutions. Most people accept income as a fair tax since ______.