Whenever Congress authorizes Treasury and the IRS to make regulations, Congress is authorizing Treasury to interpret the law. Tax law is important because it impacts so many people. Many people in this country do not interact with federal government agencies, do not see a whole lot of association with their day to day lives of the activities of federal government agencies. There were over 150 million tax returns filed last year. Ordinary everyday citizens interact with the tax system in a way that they don't with many or even any other federal government agencies. Tax law is important because taxes represent the lifeblood of government. Irrespective of what you think the government ought to do, irrespective of how large you think the federal government ought to be or what activities it ought to pursue, very few people question the need for federal government altogether. And the federal government, in order to operate as well as to pursue the various goals that Congress has set for it, needs tax revenue in order to function. These days, tax law is important not only because the tax system raises the revenue that allows the federal government to operate and to pursue the various programs that Congress has enacted. But the tax law encompasses a variety of regulatory and social welfare programs and goals as well.