Beneficiaries, or those excluded from being a beneficiary, of a person's Last Will and Testament sometimes file litigation to challenge the Will. This is usually done based on allegations of undue influence, fraud, coercion or duress. So what happens if the challenge is successful and the Will is set-aside? Does that mean a prior Will comes back into effect or does it mean the person died intestate, i.e. with no Will? As with many things in the law, the answer is "it depends."
There is a doctrine in the law known as "dependent relative revocation." This doctrine provides that under certain circumstances, when a Will is set aside, a prior Will is revived. The crux of the doctrine revolves around the fact that most Wills provide that they revoke all prior Wills. If that is the case, then what happens if the Will revoking a prior Will is essentially thrown out as having been executed due to undue influence, duress, etc? The answer is that in certain cases, the court can interpret the intent as being that the person would have preferred to have the prior Will reinstated rather than to have his or her estate treated as if it is intestate.
Here's an example: John has a Will dated 1999 which leaves his estate to his cousin, Ben; in 2013 John executes a new Will that says it revokes all prior Wills and leaves everything to John's mistress, Angie. After John dies, Ben attacks the 2013 Will as having been executed as a result of the undue influence of Angie. If the court rules in favor of Ben and sets aside the 2013 Will, the court must decide if the 1999 Will gets reinstated or if John's estate will be probated as intestate? If the doctrine of dependent relative revocation applies, the 1999 Will would be reinstated. If not, then John died intestate.
In determining whether dependent relative revocation applies, the court looks at the testator's intent. One of the main indicia of intent is if a prior Will is sufficiently similar to an invalidated Will then a presumption arises that the person would want the prior Will to apply. However, that presumption may be rebutted by evidence of intent to the contrary.
In assessing the applicability of dependent relative revocation, the advice and counsel of an experienced probate attorney is necessary.