“When the Feds show up at your house with a search warrant, they can compel your cooperation in unlocking doors and opening safes and such. Demanding a laptop password is little different.”
They can “compel and demand” all they want. They still can’t make you do it. Opening the door keeps them from breaking it down or cutting open a safe. Demanding a password is not the same.
The potency of these sanctions ought not to be scoffed at. For example, NY Times reporter Judith Miller was sentenced to 18 months in federal prison for contempt refusing to disclose that Scooter Libby was the source for her identification of Valerie Plame as a CIA agent. Miller eventually complied and was released after serving about two and a half months.
Similarly, a disgruntled tech employee changed administrative passwords and locked out the City of San Francisco from full control of its computer system. He was jailed and soon gave up the passwords -- but was still convicted and sentenced to fours years.