History
Comparative Analysis of Presidential versus Parliamentary Systems
Quick fact
In parliamentary systems, a prime minister can be removed by a simple vote of no confidence in the legislature, often within days. In presidential systems, removing the president typically requires impeachment, a lengthy political-legal process that has rarely succeeded—only three U.S. presidents have ever been impeached, and none have been removed by that process.
Why this is interesting
You probably know that the U.S. president is a powerful leader, while the U.K.'s prime minister seems similar. But why does the prime minister lose power in days while a president can stay despite unpopularity?