Final answer:
The 1867 treaty securing the purchase of Alaska from Russia contributed significantly to U.S. expansion, providing resources and strategic advantages despite initial skepticism, and had complex effects on Alaska's native populations.
Step-by-step explanation:
On June 20, 1867, the Treaty concerning the cession of the Russian possessions in North America, commonly known as the purchase of Alaska, was signed, marking a significant moment in U.S. history. Secretary of State William Seward facilitated the purchase from Russia for $7.2 million, which was initially met with skepticism and nicknamed Seward's Folly and Seward's Icebox. However, the acquisition proved to be strategically advantageous, giving the U.S. access to vast natural resources, including the gold that spurred the Klondike Gold Rush. Moreover, the deal provided the United States with additional fish, furs, and coaling stations for merchant ships, contributing significantly to the country's expansion and industrial development.
Despite the economic benefits, the transfer of Alaska led to challenges for the native populations, magnified by the industrial developments in the region. The indigenous and Russian cultures faced upheaval as the U.S. exploited the area's mineral wealth. It wasn't until the Alaska Native Claims Settlement Act in 1971 that Alaska Natives received compensation for their ancestral land claims, highlighting the complex legacy of U.S. territorial expansion.