How does the 1854 Kansas-Nebraska Act create another crisis over slavery?

Click-on: Learn about this by reading these chapters in the History Book: 

• Chapter 42. A Crisis Over Slavery Is Averted By The “Missouri Compromise”
• Chapter 157. Douglas Drives His 1850 Compromise Bills Through Congress
• Chapter 179. Congress Passes The Controversial Kansas-Nebraska Act
• Chapter 180. A Nascent “Republic Party” Is Formed To Oppose The Kansas-Nebraska Act