10. Colorado Legalizes Recreational Marijuana (2012)
In 2012, Colorado became the first state to legalize recreational marijuana through the passage of Amendment 64, allowing adults 21 and over to possess and cultivate limited amounts of marijuana. This move openly contravened federal drug laws, prompting the federal government to reconsider enforcement strategies. The success of Amendment 64 influenced other states to pursue similar legalization measures (colorado.gov).
