  It has long been accepted that a possible mechanism for explaining the
existence of magnetic white dwarfs is the merger of a binary white dwarf
system, as there are viable mechanisms for producing sustainable magnetism
within the merger product. However, the lack of rapid rotators in the magnetic
white dwarf population has been always considered a problematic issue of this
scenario. In order to explain this discrepancy we build a model in which the
interaction between the magnetosphere of the star and the disk induces angular
momentum transfer. Our model predicts that the magnetospheric interaction of
magnetic white dwarfs with their disks results in a significant spin down, and
we show that the observed rotation period of REJ 0317-853, which is suggested
to be a product of a double degenerate merger, can be reproduced.
