T he Patient Protection and Affordable Care Act (ACA; P.L. 111-148 ) was signed into law on March 23, 2010. On March 30, 2010, the Health Care and Education Reconciliation Act (HCERA; P.L. 111-152 ) was signed into law, which included new provisions and amended several ACA provisions. Collectively, the laws comprise numerous provisions, most of which relate to how health care in the United States is financed, organized, and delivered. Since enactment of the ACA and HCERA, lawmakers have repeatedly debated the laws' implementation and considered bills to repeal, defund, or otherwise amend them. This report summarizes legislative actions taken during the 111 th -115 th Congresses to modify the health care-related provisions of the ACA and HCERA. (From this point forward, all references to the ACA in this report refer collectively to the law and to the changes made by HCERA, unless otherwise noted.) The first part of the report provides a brief overview of the ACA's core provisions and its impact on federal spending and health insurance coverage as context for the other material presented in the report. The second part of the report includes Table 2 , which summarizes laws enacted during the 111 th -115 th Congresses that modified ACA provisions. The third part of the report lists bills passed in the House or the Senate during the 111 th -115 th Congresses that would have modified ACA provisions, had they been enacted. Identifying legislation that modifies the ACA has become increasingly difficult over the years. This is because of the vast number of ACA provisions, their complexity, and the fact that these provisions are codified in many different parts of the U.S. Code . As a result, the legislation presented in this report's tables may not include all enacted legislation that modifies the ACA or all House- or Senate-passed legislation that would have modified the ACA, had it been enacted. Due to the increasing complexity of tracking such legislation and concerns about the ability to do so authoritatively, the Congressional Research Service (CRS) does not intend to update this report. The ACA has 10 titles ( Table 1 ), and each title has many provisions. The provisions in Titles I-VIII largely relate to how health care in the United States is financed, organized, and delivered. Title IX contains revenue provisions. Title X reauthorizes the Indian Health Care Improvement Act, establishes some new programs and requirements, and amends provisions included in the other nine titles of the ACA. A primary goal of the ACA was to increase access to affordable health care for the medically uninsured and underinsured. To that end, the law includes a complex set of interconnected provisions that address the private health insurance market and the Medicaid program. For instance, the law established financial subsidies for eligible individuals purchasing private insurance through health insurance exchanges and expanded eligibility for Medicaid. The costs to the federal government of expanding access to private insurance and Medicaid coverage were projected to be offset by increased taxes and revenues and by reduced spending on Medicare and other federal health programs. The ACA established several new taxes on firms in the health care sector and expanded existing taxes on individuals. The law includes many different provisions affecting the Medicare program, such as provisions concerning payment and program modifications to Medicare's fee-for-service program, the Medicare Advantage program, and the outpatient prescription drug program. In addition, the ACA contains hundreds of other provisions that address health care access, costs, and quality. The ACA includes provisions intended to increase the primary care and public health workforce, promote preventive services, and strengthen quality measurement, among other things. Other ACA provisions include programs to prevent elder abuse, neglect, and exploitation; a new regulatory pathway for licensing biological drugs shown to be biosimilar or interchangeable with a licensed biologic; and new nutrition labeling requirements for chain restaurant menus and vending machines. The Congressional Budget Office (CBO) and the Joint Committee on Taxation (JCT) issued the first cost estimate of the ACA on March 20, 2010. They issued an updated estimate in February 2011. According to the February 2011 estimate, the ACA would reduce federal deficits by $210 billion over the 10-year period FY2012-FY2021, and the number of non-elderly uninsured individuals would be reduced by about 34 million in CY2021. CBO and JCT have not issued an updated cost estimate of the ACA in its entirety since February 2011; however, they have issued many other ACA-related cost estimates and analyses. The estimates have changed over time due to changes in the economy, the effects of enacted legislation, technical changes in the agencies' analyses (e.g., new survey and agency data on enrollment in health care programs), and the effects of administrative and judicial decisions (e.g., the 2012 U.S. Supreme Court decision effectively making state participation in the ACA Medicaid expansion voluntary). Table 2 summarizes legislation amending the ACA that has been enacted since March 30, 2010. Each table entry identifies the Congress in which the law was enacted, provides the public law number and date of enactment, and offers a brief description of the change(s) made to the ACA. The laws are listed in reverse chronological order, beginning with the most recently enacted legislation and extending back to the first measure signed into law following enactment of the ACA and the accompanying package of amendments in the HCERA. During the 111 th Congress, a number of clarifications and technical adjustments to the ACA were enacted. In the 112 th -115 th Congresses, several more substantive ACA amendments were signed into law. For example, Title VIII of the ACA—the Community Living Assistance Services and Supports (CLASS) Act—which would have established a voluntary, long-term care insurance program to pay for community-based services and supports for individuals with functional limitations was repealed. Lawmakers also repealed a tax-filing provision (IRS Form 1099) that had been included in the ACA. In multiple separate legislative actions, lawmakers both appropriated funding for programs established under the ACA (e.g., the Community Health Center Fund) and rescinded funding for other programs established under the ACA (e.g., the Prevention and Public Health Fund). In compiling Table 2 , CRS made decisions about which laws—or which specific provisions in a particular law—to include. CRS elected to include only those provisions that made changes (including funding extensions or rescissions) to new programs and activities first authorized and funded by the ACA. CRS generally excluded provisions addressing established programs and activities that predate the ACA but were extended or amended in a non-substantive way by the law. For example, the ACA extended multiple existing Medicare and Medicaid program payments and activities that since have been further extended and/or modified by provisions in more recently enacted laws. The ACA also extended funding for a number of existing grant programs whose funding has been further extended by provisions in newer laws. None of these types of provisions are included in Table 2 . In addition to considering ACA repeal or amendment in authorizing legislation, lawmakers have used the annual appropriations process to eliminate or provide funding for ACA provisions and to modify provisions of the law. Table 2 includes provisions in appropriations legislation that have the effect of making new law or changing existing law. As an example, the Consolidated Appropriations Act, 2016 ( P.L. 114-113 ), included a temporary moratorium on the ACA's medical device tax and the annual fee on health insurance providers, as well as a two-year delay of the ACA's excise tax on high-cost employer-sponsored health plans (often referred to as the Cadillac tax ). However, Table 2 does not include provisions in appropriations legislation that address administrative spending for covering the costs of ACA implementation (e.g., denial of agency requests for new funding to help support ACA implementation); limit or restrict the use of funds provided under a bill for a specific purpose (e.g., language prohibiting an agency from using any of the funds appropriated to the agency for ACA implementation activities); or establish reporting or other administrative requirements regarding implementation of the ACA (e.g., language instructing an agency to provide an accounting of administrative funding on ACA implementation). As noted, identifying legislation that modifies the ACA has become increasingly difficult over the years. As a result, Table 2 may not provide a comprehensive list of enacted legislation that has modified the ACA. The tables in this section list legislation that passed the House ( Table 3 ) or the Senate ( Table 4 ) in the 111 th -115 th Congresses that would have modified health care-related provisions of the ACA. None of the bills listed in Tables 3 or 4 became law (although provisions included in the bills may have been added to other legislation that became law). Generally, Tables 3 and 4 list only legislation that, if enacted, would have had a direct impact on the ACA and its implementation; measures that would not have had such an effect are not included. Thus, budget resolutions, which are binding only on certain procedural matters before Congress, are not included. The House-passed legislation included stand-alone bills as well as provisions in broader, often unrelated measures. Four of the House-passed bills listed in Table 3 would have repealed the ACA in its entirety: H.R. 596 in the 114 th Congress; H.R. 45 in the 113 th Congress; H.R. 6079 in the 112 th Congress; and H.R. 2 in the 112 th Congress. The other House-passed bills listed in Table 3 would have (1) repealed, restricted, or otherwise limited, specific provisions in the ACA; (2) eliminated appropriations provided by the ACA and rescinded all unobligated funds; (3) replaced the mandatory appropriations for one or more ACA programs with authorizations of (discretionary) appropriations and rescinded all unobligated funds; or (4) blocked or otherwise delayed implementation of specific ACA provisions. The Senate passed considerably fewer bills that would have modified the health care-related provisions of the ACA than did the House in the 111 th -115 th Congresses ( Table 4 ). None of the Senate-passed bills listed in Table 4 would have repealed the ACA in its entirety. Two of the three bills listed in Table 4 would have repealed or amended specific provisions in the ACA, and the third bill would have extended a program that was modified under the ACA. As noted elsewhere in this report, identifying bills that would modify the ACA has become increasingly difficult. As a result, Tables 3 and 4 may not provide comprehensive lists of House-passed and Senate-passed bills that would modify the ACA. 

Summary: The Patient Protection and Affordable Care Act (ACA; P.L. 111-148) was signed into law on March 23, 2010. The law comprises numerous provisions in 10 titles. The provisions in Titles I-VIII largely relate to how health care in the United States is financed, organized, and delivered. Title IX contains revenue provisions. Title X reauthorizes the Indian Health Care Improvement Act, establishes some new programs and requirements, and amends provisions included in the other nine titles of the ACA. On March 30, 2010, the Health Care and Education Reconciliation Act (HCERA; P.L. 111-152) was signed into law, which included new provisions and amended several ACA provisions. Since enactment of the ACA and HCERA, lawmakers have repeatedly debated the laws' implementation and considered bills to repeal, defund, or otherwise amend them. This report summarizes legislative actions taken during the 111th-115th Congresses to modify the health care-related provisions of the ACA and HCERA. The first part of the report provides a brief overview of the laws' core provisions and their impact on federal spending and health insurance coverage as context for the other material presented in the report. The second part of the report includes Table 2, which summarizes laws enacted during the 111th-115th Congresses that modified ACA or HCERA provisions. The third part of the report lists bills passed in the House or the Senate during the 111th-115th Congresses that would have modified ACA or HCERA provisions, had they been enacted. Identifying legislation that modifies the ACA and HCERA has become increasingly difficult over the years. This is because of the vast number of ACA and HCERA provisions, their complexity, and the fact that these provisions are codified in many different parts of the U.S. Code. As a result, the legislation presented in this report's tables may not include all enacted legislation that modifies the ACA or HCERA, or all House- or Senate-passed legislation that would have modified the ACA or HCERA, had it been enacted. Due to the increasing complexity of tracking such legislation and concerns about the ability to do so authoritatively, the Congressional Research Service (CRS) does not intend to update this report.