this author speaks clearly about how the empire expanded at mexico's expense and may be attempting to again but this time at denmarks expense;

Both Denmark and Greenland are reacting negatively to President Trump’s expressed interest in purchasing Greenland, an autonomous country within the Kingdom of Denmark. Danish Prime Minister Mette Frederikson called Trump’s idea “absurd.” A spokesman for Greenland’s premier Kim Kielson, stated, “Greenland is not for sale.”

Is that the end of the controversy? Not necessarily. Just ask the Mexican people. After their government rejected an offer by U.S. officials to purchase the northern half of their country, they ended up losing it anyway through U.S. military force.

In 1845, newly elected U.S. President James Polk made an offer to Mexico to purchase what amounted to the states of California, New Mexico, Arizona, and Texas. The previous year Texas had been annexed by the United States as the nation’s 28th state, but the annexation had not been agreed to by Mexico, which continued to claim Texas as part of Mexico.

Mexico turned down Polk’s offer, but Polk would not be dissuaded. Instead, he began looking for an opportunity to go to war with Mexico, which, if the U.S. was victorious, would permit the U.S. government to simply steal the land it was trying to purchase.

Polk’s challenge was to find a way to make it look like it was Mexico, rather than the United States, that started the war. That way, Polk could claim that the United States was simply defending itself against an aggressive power and then claim his booty as part of a treaty that would end the war.......https://www.fff.org/2019/08/19/greenland-and-denmark-prepare-your-defenses/