An array of budget process reform proposals are put forth each year seeking to refine or improve the existing constitutional requirements, laws, and rules that make up the federal budget process. Some proposals are designed not only to modify the budget process, but also to produce specific budgetary outcomes. Particularly popular when there is dissatisfaction with debt or deficit levels, such proposals seek to establish a legal mandate for a budgetary policy or fiscal objective, such as a specific limit on the deficit level, or the requirement for a balanced federal budget. This report focuses specifically on one such budget process reform: the concept of creating a statutory limit on total spending. A total spending limit, often referred to as an overall spending cap or an omnicap, consists of statutory long-term or permanent limits on federal spending, encompassing both discretionary and direct spending (also referred to as mandatory or entitlement spending). Further, the analysis in this report concerns measures that propose a total spending limit that also include an automatic statutory mechanism to enforce the spending limit in the event that compliance is not achieved through legislative action. This form of cap should be distinguished from other mechanisms that may limit spending, but do not include an automatic means to enforce the specified levels. For example, this report excludes proposals to create total spending limits that are enforced only by points of order, or proposals to institute a constitutional amendment requiring a balanced budget, which generally lack any automatic enforcement mechanism. Generally, total spending limits would operate by first establishing in statute a specific total spending limit for each year. At some point during each year, Congress would be informed of a projected overall spending total and the amount, if any, by which the statutory spending limit is projected to be breached. After a period of time, during which Congress would presumably attempt to achieve compliance with the spending limits through legislative action, a final determination would be made as to whether the spending limit had been breached. In the event of a breach, an automatic enforcement mechanism would impose reductions in spending. As with many features of the proposals, the proposed enforcement mechanisms could vary significantly. They may include exemptions for specific programs, as well as provide for suspension of enforcement under specific circumstances, such as war. The recent growth in spending, both in dollar terms and relative to the economy as a whole, has garnered support for total limits on spending. Several groups and organizations have recommended a total spending cap, though few provide detail on what such a legislative proposal might include. Some legislative proposals have been introduced in the 112 th Congress, however, such as S. 245 , introduced by Senator Bob Corker, and a companion measure, H.R. 1605 introduced by Representative John J. Duncan Jr.; H.R. 1848 , introduced by Representative Connie Mack; H.R. 2041 , introduced by Representative Jack Kingston; and H.R. 2560 , introduced by Representative Jason Chaffetz. In addition, the House-passed budget resolution for FY2012, H.Con.Res. 34 , includes a policy statement on budget enforcement that calls for Congress to enact total spending limits, and on July 19, 2011, the House passed H.R. 2560 , which includes total spending limits for FY2013-FY2021. The following sections provide a general discussion of the objectives, challenges, and criticisms of total spending limits. The next section of the report discusses typical features of total spending limits and provides information on how they may vary. The final section of the report includes observations on compliance with the spending limits, based on historical experiences with statutory budget controls. The main objective of total spending limits appears to be to acknowledge and address a recent growth in federal spending. In FY2000, total federal outlays equaled 18.2% of gross domestic product (GDP). By FY2010, total federal outlays reached 23.8% of GDP. Under the CBO baseline, totals outlays are projected to reach 24.0% of GDP in FY2021 under current policy. Further, overall spending limits apparently intend to address the growing deficit and debt levels. Concern has grown over an increasing deficit and its potential effect on the nation's fiscal and economic health. The budget deficit each year from 2009 to 2011 has been the highest ever in dollar terms and significantly higher as a share of GDP than in any other year since World War II. The budget is not projected to be on a sustainable path under current policy, in the sense that the federal debt will continue to grow more quickly than GDP. Although there has been no difficulty financing the deficit to date, at some point, investors could refuse to continue to finance deficits that they believed were unsustainable. Although some lawmakers advocate a combination of spending decreases and revenue increases to address the deficit, proponents of total spending limit proposals have often been associated with the belief that all or much of deficit reduction policy should take place through decreases in spending. Although a spending limit could theoretically be combined with revenue increases, current proponents of spending limits typically seek to assure that reductions in spending be primarily used to confront the growing deficit. There are additional objectives underlying the concept of statutory spending limits, which is particularly noticeable because the congressional budget resolution already exists as a method of setting and enforcing desired spending levels. Statutory limits on total spending address at least two perceived limitations of the congressional budget resolution. First, the levels in the congressional budget resolution are generally enforced by raising points of order on the House and Senate floor against provisions in budgetary legislation. Such an enforcement mechanism relies on Members affirmatively raising points of order against the legislation, and most of these points of order can be waived by a majority or super-majority of each chamber. Further, points of order can limit spending only in new legislation being considered by Congress; they cannot limit spending that results from previously enacted legislation, from which more than half of current spending arises. Total spending limits would establish a more stringent enforcement mechanism, one that would be automatically triggered to make cuts to already enacted spending, and could only be waived though the enactment of further legislation. This could possibly overcome what some perceive as institutional barriers to cutting spending. For example, although many lawmakers may favor decreases in spending, reaching legislative agreement on which programs specifically should be cut is difficult, both procedurally and politically. An automatic reduction mechanism would tend to ensure the occurrence of spending cuts, even without legislative agreement. Second, although the congressional budget resolution sets a desired level of overall spending for a specific year, the budget resolution is not required to adherence to any specific budgetary policy. Further, Congress is not required to maintain any specific spending levels from one annual budget resolution to the next. The same is true for the President's annual budget submission. Further, no alignment is required between the spending levels proposed in the President's budget submission and those established by the congressional budget resolution. Statutory limits on total spending would establish a federal budgetary policy which would likely require that the spending levels in the President's budget proposal and the congressional budget resolution align. Alleviating future controversy over appropriate levels of overall annual spending may facilitate the development and agreement on substantive policy changes to achieve the spending limits. Furthermore, setting total spending caps would establish a federal budgetary policy that remains consistent year after year, despite changes in the presidency or Congress. The implementation of any overall spending limit may raise difficulties stemming from several causes. First, as mentioned above, the levels of spending stipulated under any cap would presumably have to be established on the basis of economic and fiscal projections that inherently involve some uncertainty. The level of spending may also be affected by unforeseen events that budgetary projections cannot take into account even through estimates. Finally, levels of direct spending are especially subject to unpredictable variations. Using projections as a basis for budgetary decisions can be problematic because they are highly sensitive to small changes in underlying assumptions and economic factors and are subject to substantial margins of error, even over short periods of time. Based on history, actual outcomes can be much better or worse than projections. The Office of Management and Budget (OMB) estimates that the absolute average errors for its budget deficit projections are 1.5% of GDP for the next budget year and 3.5% of GDP for five years in the future. Making programmatic changes to achieve fiscal goals based on these projections, therefore, must be expected to result in changes that ultimately over- or under-shoot what is intended. Furthermore, as described below, under certain circumstances, the need to base estimates on projections may make it possible to generate projections that conform to stipulated targets by appropriate adjustment of the assumptions underlying the projections. Unforeseen events present a dimension of uncertainty that goes beyond what is inherent to trends in current fiscal and economic activity. Many of the legislative spending increases that occurred in the past decade were due to events that could reasonably regarded as extraordinary or unforeseen, including the terrorist attacks of September 11, 2001, ongoing military operations in Afghanistan and Iraq, Hurricane Katrina and other natural disasters, and the 2008 financial crisis. Creating statutory spending caps may limit Congress's flexibility in responding to future unforeseen events, whether they be natural disasters or situations that Members conclude require increased domestic, defense, or international spending. As described below, some proposals include mechanisms such as waivers or emergency exemptions to deal with such unanticipated events as they occur, although it could be argued that creating such an exemption mechanism risks compromising the overall goals of statutory spending caps. One of the most intricate complications that overall spending targets must address would arise from their inclusion of direct as well as discretionary spending. Total spending for direct spending programs, which currently makes up over half of total federal spending and is forecast to grow rapidly in the future, is difficult to control or limit for several reasons. First, unlike discretionary spending programs, which are funded through annual appropriations, direct spending programs generally are not controlled through annual appropriations actions, but are instead controlled through other permanent or multi-year laws, meaning that most will automatically continue to operate each year, barring congressional action to the contrary.