Coronavirus pandemic Select a topic from the dropdown below to learn more.Political responses overviewState reopening plansDocumenting America's Path to RecoveryDaily updatesElection changesChanges to vote-by-mail and absentee voting proceduresFederal responsesState responsesState executive ordersStay-at-home ordersMultistate agreementsNon-governmental reopening plansEvictions and foreclosures policiesTravel restrictionsEnacted state legislationState legislative session changesSchool closuresState court closuresInmate releasesLocal government responsesDiagnosed or quarantined politiciansBallot measure changesArguments about government responsesThe 1918 influenza pandemicPandemic Response Accountability CommitteeUnemployment filingsLawsuitsSubmit On December 22, 2020, McMaster announced he had tested positive for coronavirus.

McMaster was one of 13 state attorneys general who initiated a 2010 lawsuit challenging the constitutionality of the Patient Protection and Affordable Care Act. The suit argued that the individual mandate fell outside of the federal government’s authority and that the requirement for state Medicaid expansion of coverage violated state sovereignty. The case was ultimately heard before the Supreme Court, which ruled to uphold the individual mandate as falling within Congress’ authority to levy taxes and struck down the Medicaid expansion as being unduly coercive in light of the withholding of funding that would result from noncompliance.

Following the passage of President Barack Obama's healthcare reform legislation in 2009, McMaster joined 13 other Republican state attorneys general in questioning the constitutionality of a provision within the Senate version of the bill and exploring potential legal challenges to the measure as well. The attorneys general alleged that United States Senate Majority Leader Harry Reid struck a deal with Nebraska Senator Ben Nelson to recruit him as the 60th vote needed to pass the measure. The deal allegedly gave Nebraska exemption from its share of the Medicaid expansion, which, according to Politico, was "expected to cost the federal government $100 million over 10 years." Nearly a week and a half later, Senator Nelson called upon McMaster to "call off the dogs" and forgo any legal action until negotiations in Congress over the final health care bill had concluded. The morning after the United States House of Representatives narrowly passed the Senate reconciliation bill, allowing the Affordable Care Act to move forward, McMaster announced his intention to join with Florida Attorney General Bill McCollum in challenging the legislation, which he described as "clearly unconstitutional." According to a report by ABC 15 News, McMaster argued that "the measure violates state sovereignty because it requires all Americans have some form of health insurance." In a 7-2 ruling on June 28, 2012, the U.S. Supreme Court upheld the legality of the law's individual mandate, which introduced tax penalties for those without health insurance. The court ruled that the provision in the law mandating that states expand their Medicaid programs was unconstitutional, leaving state governments with the ability to decide whether to expand Medicaid.