There are many reasons why a person might leave a spouse or another loved one out of his or her will. It is possible that the will in question was executed prior to a marriage and was never properly updated. It may also be the case that the husband and wife, though still technically married, are estranged, and do not contribute to one another's support. An end of life revelation of a past infidelity may anger a spouse enough to rewrite his or her last will and testament. Individuals may make rash decisions to disinherit spouses based on a single argument or misunderstanding. This can be exacerbated by symptoms of dementia. Regardless of the reason, a person who is not named in his or her spouse's will may petition the court for the spousal share to receive a portion of the estate.

The spousal share of an estate, also called an elective share, is a holdover from the concept of dower in English common law. Traditionally, dower is a portion of a man's estate guaranteed to a wife when she is widowed to ensure that she does not fall into poverty after her husband dies. The practice continues today without the same restrictions on gender. Every state in America has a provision in its laws to protect an individual whose spouse dies from being left with nothing. Similar provisions for children also exist in some states. Attempts have been made to introduce legislation to protect unmarried romantic partners the same way as married couples, but these attempts have had little success.

The structure of these protections vary from state to state. The value of the estate for the purposes of establishing the spousal share may include the widow's assets depending on the jurisdiction. Some states provide a widowed spouse a larger share of the deceased's estate than others, but almost every state prohibits an individual from disinheriting a spouse entirely. The one state that does not permit an elective share to the spouse in a probate case requires that an estate pay a disinherited spouse financial support for up to one year after the death.