Passports are a federal ID, but they’re not mandated in the same way that other countries like Estonia mandate national IDs. SSNs? Sure, they’re (optionally) u

Passports are a federal ID, but they’re not mandated in the same way that other countries like Estonia mandate national IDs. SSNs? Sure, they’re (optionally) used as an identifier. But they’re primarily used in the financial world, along with your credit score. Most state and federal agencies won’t require an SSN for official business (again excepting taxes & payments). A hotel will accept a Global Entry card for check in. UPS will accept a non-driver’s license to pick up a package. You can vote with a student ID in some states. And don’t forget people who are undocumented immigrants or on F-1 and J-1 visas who don’t even have a SSN, but still need to open US bank accounts, pay taxes, get US driver’s licenses, and vote in municipal elections. Identification is complicated in the US!