In the United States, laws about what might vary from state to state?

In the United States, the federal system of government allows states to have significant control over their own laws and regulations. This means a wide variety of laws can vary from state to state, including but not limited to:

1. **Criminal Law**: What constitutes a crime and how crimes are prosecuted can vary. The death penalty, for instance, is legal in some states and outlawed in others.

2. **Traffic Laws**: Speed limits, DUI/DWI laws, and regulations concerning the use of mobile devices while driving are examples of traffic laws that can differ by state.

3. **Marriage and Family Law**: Ages of consent, same-sex marriage laws (though federally recognized), divorce laws, and adoption regulations can vary across states.

4. **Gun Control**: States have different regulations concerning the purchase, possession, and carrying of firearms.

5. **Drug Policies**: The legality of substances such as cannabis for medical or recreational use can differ from one state to another.

6. **Business Law**: Regulations on how businesses are formed, governed, and taxed can vary. Some states are known to be more business-friendly than others.

7. **Environmental Regulations**: States may have different policies and regulations relating to environmental protection and natural resource management.

8. **Education**: States set their education standards, including curricula requirements, graduation requirements, and school funding models.

9. **Employment Law**: Minimum wage, overtime pay, workers' compensation, and anti-discrimination laws can all differ among states.

10. **Voting and Elections**: Voter identification laws, early voting, and mail-in ballot provisions are all subject to state law.

11. **Taxation**: There is a diversity of state income tax, property tax, sales tax, and other taxation policies from state to state.

12. **Healthcare**: Medicaid expansion under the Affordable Care Act and other healthcare regulations can be different depending on the state.

13. **Consumer Protection**: States have varying laws regarding consumer rights and regulations, such as lemon laws for vehicles and regulations for predatory lending.

14. **Real Estate and Property Law**: Property laws, landlord-tenant laws, and homeowners association regulations can significantly differ among states.

15. **Estate and Inheritance Law**: States have their own rules concerning wills, probate, and inheritance taxes.

These differences are possible because the United States Constitution provides for a federal system, wherein the federal government has exclusive jurisdiction over certain areas while states retain broad powers to legislate on matters not expressly preempted by federal law.