Search: suicide laws us
Why: In Australia, a 49 year-old quadriplegic man wants to be allowed to starve to death. (Story here.)
Answer: Yes and not really.
"In the U.S. suicide has never been treated as a crime nor punished by property forfeiture or ignominious burial. (Some states listed it on the books as a felony but imposed no penalty.) Curiously, as of 1963, six states still considered attempted suicide a crime--North and South Dakota, Washington, New Jersey, Nevada, and Oklahoma."By the early 1990s only 2 states still listed suicide as a crime, and these have since removed that classification.
In some U.S. states, suicide is still considered an unwritten "common law crime." This means suicide can bar recovery / damages for the family in a lawsuit unless the suicidal person can be proven to have been "of unsound mind."
In many jurisdictions, medical facilities can or must commit anyone whom they believe to be suicidal for evaluation and treatment.
Source: The Straight Dope, Wikipedia
The More You Know: In 117 AD, the Roman emperor Hadrian declared attempted suicide by soldiers a form of desertion and made it a capital offense.