Proposition 42 would prohibit new state taxes based on ownership or control of personal property—including financial assets, investment accounts, business interests, retirement accounts, and intellectual property—and prohibit certain taxes that apply retroactively to conduct, activity, or status occurring before the tax takes effect. The amendment contains limited exceptions and applies to taxes enacted or taking effect on or after January 1, 2026, including measures appearing on the same ballot. State fiscal analysts say the measure could reduce future revenues by preventing tax approaches the state might otherwise adopt. People should generally know the tax consequences of a decision when they make it. The harder question is whether that principle belongs permanently in the Constitution when future lawmakers may face tax systems or fiscal problems voters cannot anticipate today.