Final answer:
The American motivation for engaging with China and Japan in the mid-19th century was driven by economic interests and imperialist aims, enshrined in the concept of manifest destiny. The treaties with Japan, forged by Matthew Perry, and efforts to tap into China's vast market, through the Open Door policy, underscored both the desire for economic expansion and the aggressive imperialist tendencies of the era.
Step-by-step explanation:
The fundamental motivations behind the new American engagement with China and Japan in the 1840s and 1850s can be attributed to a mixture of economic interests and an imperialist mindset driven by the belief in manifest destiny. Treaties such as those negotiated by Caleb Cushing and Matthew Perry have characteristics of both economic and cultural exchange and expansionist policies of the era.
The Meiji Restoration was a direct consequence of Japan witnessing the impact of modern weapons wielded by European imperialists on China. This led Japan to proactively open itself up to learning from Western advancements during a period of rapid industrialization and modernization.
Meanwhile, the Open Door policies in China were a clear indication of the United States' intention to exploit the vast 'China Market.' The United States, using the defeat of the Spanish navy and the acquisition of the Philippines, pursued this lucrative market that had the potential to absorb American manufactured goods. The later treaties enforced upon Japan by Commodore Perry were marked by the same aggressive approach, aiming to secure American interests under the guise of establishing trade relations.
Ultimately, it is clear that while economic interests and the desire for cultural exchange played a role, the treaties and interactions with East Asia during this period were heavily influenced by the American expansionist spirit and were reflective of the general Western imperialist ambitions of the time.