Raymond Lucia, of "Buckets of Money" fame, is entitled to a new trial, the court ruled.
The court sided with states and traditional retailers on a 5-4 vote.
The issue is whether false statements are enough to hold someone liable for a fraudulent scheme.
The justices rejected arguments from scouts who claimed the 30 teams were colluding to suppress wages.
The ruling builds on previous Supreme Court decisions that let companies channel disputes into arbitration.
Nevada is the only state where single-game wagering is now legal.
With Trump support, he says the SEC's judge who handled his case was appointed in violation of the Constitution.
The issue is whether some types of stock workers receive through options qualify as taxable compensation.
The court challenge to the agency's in-house trials could affect more than 100 cases currently at the SEC.
A discussion about a wedding cake has grown into a Supreme Court collision of some of the nation’s most cherished values.