Why did Roosevelt intervene in negotiations to end the Russian Japanese war?

President Theodore Roosevelt intervened in the negotiations to end the Russo-Japanese War in 1905 to promote peace and stability in East Asia, as the conflict threatened American interests in the region. He sought to prevent the expansion of Japanese influence, which could disrupt the balance of power, and to assert the United States' role as a mediator in international affairs. His successful facilitation of the Treaty of Portsmouth earned him the Nobel Peace Prize and elevated the U.S. position on the global stage.