There are a few traditional grounds for a Will contest:
- There was a defect in the way the Will was signed or witnessed. Examples include forgery, or the fact that the Will was witnessed by someone before the Testator signed the Will.
- The decedent lacked legal capacity to make a Will at the time the Will was signed.
- The decedent was the victim of undue influence of another person, which overcame the decedent's true desires regarding the disposition of his own estate.
- The decedent suffered from an insane delusion that affected the dispositive provisions of the will.
The above grounds for a will contest typically require an expert medical opinion concerning lack of capacity or undue influence.
Aside from the traditional grounds, there are other grounds based upon statutes:
- The Will, dated before the divorce, leaves property to the former spouse.
- The Will, dated before the present marriage, fails to provide for present spouse.
- The Will fails to provide for one or more after-born children.
- The Will fails to make provision for the children of a prior marriage.
- The Will specifically disinherits present spouse, but she is still entitled to the package of widow's allowances and exemptions.
Sometimes, the meaning of a Will is not clear. In a famous Tucson will case, Hazel Smith's will read:
"I devise my money and coin collection to Todd Fehlhaber and Sue Fehlhaber in equal shares, or to the survivor thereof."
The question was whether large bank accounts were included in term "money". This case is an example of a patent ambiguity, or an unclarity of meaning that appears from the face of the Will. By the way, the Court decided the case by referring to an affidavit submitted by the lawyer who drafted the will. He explained that his client had meant to give her coin collection to the Felhaber's and not her bank accounts. The Court was careful to point out that this outside evidence would not have been admissible had the Will not contained an ambiguity.