That diplomacy is now in jeopardy. In late April, President Donald Trump signed an executive order calling for the Department of the Interior to review national monuments created under previous administrations, dating back to 1996. The deadline for Interior Secretary Ryan Zinke’s review of the monument is June 10.

The 1906 Antiquities Act grants the president the power to create national monuments. During his time in office, Obama designated more national monuments than any other president. In response, Trump has taken a cue from Utah political leaders and criticized his predecessor. Announcing the monument review in April, with Utah Governor Gary Herbert and much of the state’s congressional delegation by his side, Trump chided Obama’s use of the Antiquities Act. “It’s gotten worse and worse and worse, and now we’re going to free it up,” he said. “This should never have happened.”

Should the Bears Ears review result in a downsizing, or outright revocation of the monument status, it would be the latest example of the federal government setting aside land in conjunction with tribes, only to break the agreement.

“Take the example of the Ute tribes,” said Monte Mills, an assistant professor of American Indian law at the University of Montana. Prior to European-American settlement, the Ute territory stretched across much of Colorado and Utah—Bears Ears included—and as far south as New Mexico. “As non-Indian settlers moved in, the federal government negotiated a treaty in 1868 that recognized their reservation boundaries essentially as the western third of Colorado. Within five years, there was a portion cut out because of the discovery of gold and silver.” A Ute attack on an Indian agency led the government to evict northern Utes from Colorado; their reservation is now in Utah’s oil and gas country. The Southern and Ute Mountain Ute reservations are in Southwest Colorado, south of the mineral-rich San Juan Mountains.

Similar scenarios have unfolded in other parts of the United States, as well. An 1855 treaty granted many Washington state tribes the “right of taking fish at usual and accustomed grounds,” but Native American fishing was nonetheless regulated by the state. Immigrants with larger commercial fishing vessels quickly displaced tribal fishing operations, and Indians were required to purchase recreational fishing licenses. Tribes responded with the “Fish War” protests in the 1960s and 1970s, and in 1974, a district court ruling granted tribes half of Washington’s fish harvest.

In 1868, the federal government promised the Sioux tribes the western part of South Dakota; nine years later, it would seize the Black Hills region after gold was discovered there. The Supreme Court ruled in 1980 that the land was illegally taken and that the Sioux should be compensated. The tribe refused to take the federal money, saying the land was never for sale.