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In California, this supermajority fraction of the Legislature must approve all tax increases.
What is 2/3? California Proposition 13, or the People's Initiative to Limit Property Taxation was on the June 6, 1978 statewide primary ballot in California as an initiated constitutional amendment, where it was approved. The two main objectives of Proposition 13 were to freeze the tax-assessed value of properties at the time of purchase, and to require that when legislative bodies in the state (either the state legislature or local governing boards) wanted to raise taxes, a two-thirds majority vote is required.