No, you cannot operate a horse and buggy while drunk. Driving a vehicle of any sort requires the driver to be in full control of their senses, and alcohol or drugs can severely impair one's ability to make decisions and respond quickly to changing conditions. Additionally, operating a horse-drawn vehicle is more dangerous than driving an automobile as horses are living creatures with minds of their own that can react unpredictably. Drunk driving puts both the person behind the wheel and anyone else on the road at risk for injury or death due to decreased reaction times, impaired judgment, and other factors associated with being under the influence. Furthermore, most states have laws prohibiting people from operating any motorized vehicles while intoxicated so even if someone were successful in maintaining some level of control over their horse-drawn carriage it would still be considered illegal in most places.