The Social Democratic Party of Japan (SDP) is a political party that advocates for social justice, equality, and democratic socialism. Founded in 1996, it emerged from the merger of the Japan Socialist Party and other left-leaning groups. The SDP aims to address issues such as workers' rights, environmental protection, and social welfare. The party has historically played a significant role in Japanese politics, although its influence has waned in recent years. It supports policies that promote peace and oppose militarization, aligning with its commitment to the principles of pacifism established in Japan's post-World War II constitution.