1. It
was not properly witnessed or acknowledged.
2. Forgery of
the testator's signature.
3. Procurement
of the testator's signature by fraud or
duress.
4. The
testator's lack of the requisite mental capacity. This
involves not being able to understand the nature and
extent of the testator's property and the natural objects
of his or her bounty. This is a much lower standard than
the capacity required to make contracts. Mental illness
or drug addiction by themselves do not constitute lack of
the required mental capacity.
5. Undue
influence. Anyone is entitled to influence a testator to
make a will favoring them. Undue influence is a technical
term. First the person exerting the influence must be in
a fiduciary relationship to the testator. The typical
situation involves someone holding a power of attorney
from the testator. Absent something like a power of
attorney the requisite relationship can be shown if the
testator is so reliant on the person that that person's
will becomes the testator's will. This is very hard to
show. Once there is a fiduciary relationship the person
must procure the will - that is they must prepare it or
instruct somehow to prepare it and it must favor the
fiduciary.
