British lawmakers are set to decide Friday whether to legalize assisted dying, a contentious proposal that would make the United Kingdom one of a small handful of nations to allow terminally ill people to end their lives.

The bill passes the first stage in the Commons but will be followed by months of parliamentary activity before it becomes a law.

The bill, modeled after Oregon’s law, would apply to terminally ill patients and could usher in one of the most dramatic social changes Britain has seen in years.