Which type of plea cannot be admitted as evidence in a civil trial?

A nolo contendere plea, or "no contest" plea, is a legal option for defendants in a criminal trial. When a defendant enters a nolo contendere plea, they do not admit guilt for the crime but accept the consequences of a conviction. This type of plea cannot be used as evidence in a civil trial because it does not entail an admission of guilt or liability.

The rationale behind this rule is that the nolo contendere plea is meant to prevent defendants from having their decision to plead used against them in subsequent civil proceedings. It allows them to accept a conviction without the implication that they are admitting to the tortious or criminal behavior that may lead to civil liability.

In contrast, a guilty plea is an admission of guilt and can potentially be used as evidence in civil trials. A not guilty plea does not indicate any admission regarding the facts of the case. An Alford plea allows a defendant to plead guilty while asserting their innocence, but it can still be construed as an admission in some contexts.