A parliamentary democracy operates differently from a presidential democracy primarily in the relationship between the executive and legislative branches. In parliamentary systems, the executive, often led by a prime minister, emerges from the legislature and is directly accountable to it. This creates a fusion of powers, allowing for quicker legislative action. In contrast, a presidential democracy features a separation of powers, with an independently elected president. This division can lead to gridlock if the president and legislature belong to opposing parties, impacting the efficiency of governance.