In 2009, the Democratic Party of Japan (DPJ) rose to power in the Japanese Diet, marking the first time in more than five decades that a party other than the Liberal Democratic Party controlled the government. Some would assume this monumental shift has the potential to bring about a range of policy changes in Japan, especially in the realm of security. This thesis addresses the potential for changes in Japanese security policy by evaluating two particular elements of the maritime security realm: ballistic missile defense and antipiracy. When considering the ability of the DPJ to influence security policy in Japan, the country's political environment represents a unique situation in which party influence must be weighed against the relative influence of societal norms and external factors. Taking this into consideration, it is concluded that DPJ influence will be limited, resulting in little potential for changes in security policy, as reflected in the assessment of elements of maritime security.