Iraq is nothing like Vietnam!

Iraq is more like India, right after the British pulled out.

Before its independence, India was never a single country but a bunch of different entities. Many predicted that India, because of diversities in its cultures, religion, languages, castes, manners, local histories, nationalities and identities, would not survive as a single democratic country, but would break up into smaller countries.
Since independence, India had many political problems. During independence the most burning issues were the riots between the Hindus and Muslims while the Sikhs were siding with Hindus. Another issue was convincing the Princely states not to declare independence or join Pakistan but to join the Indian Union. India also had a few wars with its neighbors on border issues.
India also has many internal problems. Different communities with different identities - regional, language, caste, religion - demanded different rights for their communities. Some communities demanded more autonomy for their cultures within the Indian states. Others demanded autonomous states within the Indian Union, while the others demanded to be independent from India.
With all its problems India survives as a single state with democratic character.