No, it is not automatically the drunk driver's fault in an accident, even if they are intoxicated. While driving under the influence is illegal and greatly increases the risk of causing an accident, fault is determined by the specific actions that led to the collision. In some cases, the sober driver might have committed a traffic violation or acted negligently, leading to the accident. However, the fact that a driver was intoxicated can be used as evidence of negligence or recklessness in a personal injury claim. In Texas, which follows a modified comparative negligence system, if the drunk driver is found to be more than 50% at fault, they can be held liable for damages. But it's essential to investigate the specifics of the accident to determine fault accurately.