State approaches to adopting the Affordable Care Act’s Medicaid expansion have varied greatly by state based on state law, the political context, or other factors. While it does not cover how every state has enacted the Medicaid expansion, this issue brief highlights some of the different approaches states have taken to adopting the Medicaid expansion initially and how those approaches may have changed over time.

Initial Adoption of the ACA Medicaid Expansion. Each state’s circumstances are unique, and the actions taken by one state may not apply to another state’s circumstances; however, initial state approaches to adopting the Medicaid expansion generally fall into four broad categories:

  • Adoption Through the Standard Legislative Process and a State Plan Amendment (SPA). Many expansion states have adopted the Medicaid expansion through the standard legislative process – legislation was passed authorizing the Medicaid expansion (either in a stand-alone bill or as part of budget legislation) – and expansion was implemented under SPA authority.
  • Adoption Through the Standard Legislative Process and a Section 1115 Waiver. While Section 1115 waivers require additional steps to obtain federal approval, the legislative process to initially adopt the expansion remains largely the same at the state level. Some states have adopted the expansion through a combination of a SPA and waiver approach.
  • Adoption Through Executive Action and a SPA or Section 1115 Waiver. Initial enactment of the expansion has involved the legislature in most expansion states, but some governors have adopted the expansion through executive action without approval of the legislature. Other states, however, have enacted laws prohibiting Medicaid expansion without legislative approval.
  • Adoption Through a Ballot Initiative and a SPA or Section 1115 Waiver. Multiple states have adopted the Medicaid expansion through a ballot initiative. However, voter-approved ballot measures may face barriers to implementation based on state law requirements, efforts to block or amend the policies by legislators or governors, or legal challenges. Some states have sought to use ballot initiatives to secure or reject new funding sources for the state share of Medicaid expansion costs.


    State approaches to adopting the ACA’s Medicaid expansion have varied greatly by state based on state law, the political context or other factors. KFF highlights some of the approaches states have taken and how those approaches may have changed over time.

Changes in Expansion Status and/or Approach Over Time. When considering states’ approaches to expansion, it is important to keep in mind that these approaches are not static and may change over time in response to elections, new policy options, or other factors. Some states’ expansion programs have evolved over time at the direction of the state legislature or based on requirements included in the original legislation adopting the expansion. In addition, some states (including those using both SPA and waiver authority for expanded coverage) have used or are seeking Section 1115 waivers to make program changes that affect the expansion population such as adding work requirements as a condition of eligibility for coverage. Financing for the state share of expansion costs has been a major factor in the decision about expansion adoption in many states, and some states have tied expansion adoption or continuation to specific funding mechanisms for the state share of expansion costs.

Looking Ahead. Looking ahead, it will be important to monitor debates on expansion in the 14 remaining non-expansion states, monitor any potential changes to expansion programs in states that have already adopted the expansion (including developments in states that adopted expansion through a ballot initiative), and assess the advantages and disadvantages associated with different approaches with regard to coverage, cost, and administrative capacity.

Issue Brief

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An Overview of State Approaches to Adopting the Medicaid Expansion