Lower courts have split on the question, and both red and blue states urged the justices to settle the matter in advance of the "white hot" glare of the 2020 election. They say they fear a handful of independent-minded members of the electoral college deciding the next president.
"It is possible that a presidential election could turn on just a few disputed electoral votes cast in purported violation of state law," said a petition filed by three electors who faced fines from the state of Washington for not supporting Hillary Clinton, the winner of that state's popular vote in 2016.
"It is not entirely clear how that would play out - but there is a very real risk of substantial unrest, or worse, if that does happen."
The Supreme Court accepted cases from Washington and Colorado in time to hold oral arguments this spring and decide the outcome by June. It also said it will consider the Trump administration's attempt to allow some employers and universities to claim religious or moral exemptions from offering contraceptive care. It will make the third time the court has considered the requirement of the Affordable Care Act.
In the electors case, 10 members of the electoral college attempted to freelance after the 2016 election between Clinton and President Donald Trump. Five of the 58 presidential elections have been decided by smaller margins, most recently in 2000, when President George W. Bush defeated Democrat Al Gore by five electoral votes.
A brief filed on behalf of the states said that 32 states and the District of Columbia require electors to vote for the winner of the statewide vote, and asked the Supreme Court to make clear there is no constitutional prohibition on such laws.
Anything else, the state of Washington told the Supreme Court in its brief, "would mean that only 538 Americans - members of the Electoral College - have a say in who should be president; everything else is simply advisory."
The motive of those challenging the laws, the state said, "is to destroy public faith in the Electoral College so that the people decide to do away with it."
Challengers say the Constitution leaves up to states the appointment of electors, but no more than that. "There is no mechanism for state officials to monitor, control, or dictate electoral votes," said a brief filed by Harvard law professor Lawrence Lessig and his group Equal Citizens. "Instead, the right to vote in the Constitution and federal law is personal to the electors, and it is supervised by the electors themselves."
In the summer of 2016, Peter Bret Chiafalo, Levi Jennet Guerra and Esther Virginia John were nominated as presidential electors for the Washington Democratic Party. They ran pledging to vote for the party's nominee.
But when the electoral college convened after the election, all three voted for former Secretary of State Colin Powell for president, and split their votes for vice president among Sens. Maria Cantwell, D-Wash.; Susan Collins, R-Maine; and Elizabeth Warren, D-Mass.
Congress counted their votes. According to the voting advocacy group FairVote, "Congress has accepted the vote of every vote contrary to a pledge or expectation in the nation's history that has been transmitted to it - a total of more than 150 votes across twenty different elections from 1796 to 2016." As in each of those elections, the 2016 defections did not change the outcome of the race.
But Chiafalo, Guerra and John were in violation of Washington law, which requires electors to support their nominee of their party or be subject to a civil fine of up to $1,000.
The trio challenged the law and lost at the Washington Supreme Court. The majority found "the Constitution explicitly confers broad authority on the states to dictate the manner and mode of appointing presidential electors." Additionally, nothing in the document "suggests that electors have discretion to cast their votes without limitation or restriction by the state legislature."
Justice Steven Gonzalez dissented. The Constitution contemplated that electors "would be free agents," he said, "to exercise an independent and nonpartisan judgment as to who was best qualified for the nation's highest offices."
A few months later, a panel of the U.S. Court of Appeals for the 10th Circuit decided the issue along the lines Gonzalez suggested.
It was considering the Colorado secretary of state's attempt to throw out the vote of Micheal Baca, who was pledged to vote for Clinton but cast his vote for Republican John Kasich of Ohio. Baca envisioned a plan where Republicans might ditch Donald Trump in favor of someone else.
The appeals court panel took a deep dive into the Constitution's language, and a majority said the words pointed in one direction: electors are "free to vote as they choose."
"While the Constitution grants the states plenary power to appoint their electors, it does not provide the states the power to interfere once voting begins, to remove an elector, to direct the other electors to disregard the removed elector's vote or to appoint a new elector to cast a replacement vote," wrote Judge Carolyn McHugh.
The Supreme Court in 1952 ruled that states could allow parties to require those running for elector to pledge to support their party's nominees. The Washington Supreme Court extrapolated from that ruling.
But Jason Harrow of Equal Citizen said the court has not said what can happen when electors don't honor that pledge. "With this petition, we are asking the Supreme Court to resolve a critical question that has gone strangely unanswered for two centuries: who are presidential electors, and can state officials force them to vote for certain presidential candidates?"
The cases are Chiafalo v. State of Washington and Colorado Department of State v. Baca.
The contraceptive case concerns a Trump administration rule issued in 2018 that it said was an attempt to resolve long-running litigation. It made it easier for more companies and universities to claim religious exemptions to providing contraceptives through their health plans. It also allowed some employers to claim a moral exemption.
But Pennsylvania and other states objected, and challenged the rule in court. The U.S. Court of Appeals for the 3rd Circuit ruled that the administration likely lacked authority to issue such broad exemptions. It also said the administration did not comply with requirements to allow adequate public comment on the rules.
The Trump administration, and an order of nuns that has been active in fighting the contraceptive requirement for employees, asked the Supreme Court to intervene.
The combined cases are Trump v. Pennsylvania and Little Sisters of the Poor v. Pennsylvania.
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