Spousal Protections

• The laws of most states limit the extent to which your spouse can cut you out of his or her will. In the few states that follow community property rules, your spouse can only dispose of his separate property and his half of the community property in the will. In equitable distribution states, where spousal interests in marital property are considered undivided, the surviving spouse can claim a third to a half (depending upon the state) of the deceased's property no matter what the will says.
  
  

Protections For Children

• Unlike spouses, as a general rule the law doesn't protect children from getting cut out of a will. Your parents are free to leave the entirety of the estate to each other, to their new spouses, to their siblings or anyone they want. While there's usually nothing a child can do about getting left out of a will, some legal protections do exist for after-born children. An after-born child is a child who wasn't in existence at the time the will was executed; some states have provisions allowing such a child to be included under a will along with siblings even if the child himself wasn't named.
  
  

When Will Doesn't Comply With Law

• If the law in your state under your particular set of circumstances won't allow you a share of the estate but you would be otherwise entitled to take under the laws of intestate succession -- the rules that apply when somebody dies without a will -- you may be able to get some relief through a caveat proceeding. In a caveat proceeding, you can claim that the will isn't valid because it didn't comply with the formalities of state law. Some of these formalities include requirements that the will be properly signed, that it be witnessed by at least two people and that the witnesses aren't beneficiaries under the will. If the will is invalid, your state's laws of intestate succession apply.
  
  

Lack Of Capacity Or Undue Influence

• Lack of compliance with legal formalities isn't the only ground for a caveat proceeding. You may also be able to invalidate the will if you can prove undue influence -- that is, you can show that the deceased was tricked or bamboozled into signing the will and his acts weren't totally voluntary. You can also attack based upon lack of testamentary capacity; just as a mental incompetent can't enter into a contract, neither can he or she make a will. Again, if you can invalidate the will, you can then take under intestate succession.