Why did the U.S. government include a prohibition on slavery in the treaties with Native Americans in Washington Territory?

Question

(1 point)

Oto avoid the controversy of allowing slavery

Oto discourage settlers from Southern states from moving to Washington Territory

to prevent Native Americans from selling slaves to settlers

to prevent the government from promoting slavery in Washington Territory

Answer 1

to show the government's commitment to ethical treatment of Native Americans and to prevent the expansion of the institution of slavery into the territory.