Colonialism played a big role in starting nationalist movements in the 20th century.

But it also came with many challenges. Here are some of the main problems:

1. Cultural Disruption: Colonial rulers often pushed aside local cultures. This made it hard for people to feel united. Different ethnic and social groups ended up feeling separated from one another.

2. Violent Struggles: The fight for independence was often very violent. This led to civil wars and made things unstable after colonial rule ended.

3. Economic Dependence: Many countries still depended on their former colonizers for money and resources. This made it tough for them to be truly independent and self-sufficient.

4. Failures of Political Ideas: New nationalist leaders found it hard to put their ideas into practice. They struggled to create good systems of government.

To tackle these issues, future leaders should focus on:

• Building a sense of nationalism that includes everyone.
• Encouraging economic independence so countries can rely on themselves.
• Creating strong political systems to promote stability and unity for all.