How long can a retired Swede stay in the US?

A retired Swede can stay in the U.S. for up to 90 days without a visa under the Visa Waiver Program (VWP), provided they have an approved Electronic System for Travel Authorization (ESTA). For longer stays, they would need to apply for an appropriate visa, such as a tourist visa (B-2), which can allow for stays up to six months. It's important for travelers to check specific entry requirements and regulations before planning their visit.