Wow, how much time do you have?  There are countless examples of treaties signed by the US government with native tribes that respected their land boundaries or promised them material aid that were then broken.

The Sioux tribes of Montana were given blankets purposely infected with small pox so that the tribal members would get ill and die out.  This killed almost 90% of those tribes in the first two years after contact.

Geronimo was promised safety if he turned himself in but was sent to Florida with the rest of the resistance he led, far away from the Apache reservation, where he died.

Tribes were forbidden from practicing the ghost dance, a religious ceremony introduced by Sitting Bull, because they feared it would unite Native tribes against the white government.

In the modern day, Natives are given very little national attention or development funds.  The Bureau of Indian Affairs has been charged with misspending billions that was designated for tribal aid.  Reservations like Pine Ridge in South Dakota live in abject poverty with very little in the way of infrastructure (some tribal members froze to death during an ice storm this winter), even after all this time.

There are tons of examples you can cite to show that Indians (assuming you mean Native Americans and not Indians from India) have been treated unfairly in US history.

• In the 1820s and '30s, the Indians in the Southeast were moved from their homes and forced to travel to Oklahoma on the "Trail of Tears."  This was done even though the Supreme Court of the US had forbidden it.
• During the 1870s and on, Indians were taken from reservations and sent to boarding schools.  While there, they were forced to stop acting like Inidans -- they couldn't wear native clothing or hairstyles or speak their own languages.