  We offer a novel derivation of the electromagnetic self-force acting on a
charged particle moving in an arbitrary curved spacetime. Our derivation is
based on a generalization from flat spacetime to curved spacetime of the
extended-body approach of Ori and Rosenthal. In this approach the charged
particle is first modeled as a body of finite extension s, the net force acting
on the extended body is computed, and the limit s -> 0 is taken at the end of
the calculation. Concretely our extended body is a dumbbell that consists of
two point charges that are maintained at a constant spacelike separation s. The
net force acting on the dumbbell includes contributions from the mutual forces
exerted on each charge by the field created by the other charge, the individual
self-forces exerted on each charge by its own field, and the external force
which is mostly responsible for the dumbbell's acceleration. These
contributions are added up, in a way that respects the curved nature of the
spacetime, and all diverging terms in the net force are shown to be removable
by mass renormalization. Our end result, in the limit s -> 0, is the standard
expression for the electromagnetic self-force in curved spacetime.
