Answer: All the Native American tribes weren't united against their struggle with the European settlers.
Explanation: You probably recall from your history lessons that we don't have the exact number of native tribes that used to live in America. But we know they were many. More than 1.000 different groups with their own beliefs, languages and objectives.
Some groups were rivals and helped Europeans to fight with their enemies. Some groups were too kind and gave Europeans food and helped them to survive in the new world. Other groups hated Europeans and actually tried to kill them many times.
So when we speak about natives we need to have in mind that we are not talking about just one group of people. They didn't have any type of unity consciousness because they did not see each other as one same group.