Courts apply rational basis review to most laws, asking only whether the law connects rationally to any legitimate government interest. This is the lowest of three scrutiny levels the Supreme Court uses, alongside intermediate scrutiny and strict scrutiny. Under rational basis review, courts uphold nearly every challenged law. The government does not need to prove the law actually serves its stated purpose, or even name a real goal when defending it. Courts can imagine any hypothetical reason that might justify the law. Justice Story formalized this test in Nebbia v. New York, establishing that states can adopt any economic policy reasonably promoting public welfare. Only the most irrational laws fail this test. Courts use it when no fundamental rights or suspect classifications like race or religion are involved.