The Massachusetts Supreme Judicial Court ruled that the millionaire’s tax amendment can’t be included on the state’s November ballot, a decision that could have a ripple effect on several other potential ballot questions.

In a split decision June 18, five SJC justices agreed with representatives of five business groups that the proposed constitutional amendment adding a 4 percent surcharge on the state’s personal income tax rate for incomes over $1 million shouldn’t be allowed on the ballot. The amendment had...