This paper aims to analyze the keywords in the area of politics and their related words found in a large-scale newspaper corpus. These keywords and their related words can reflect the linguistic, social, and cultural changes in current Korean society(esp. with respect to politics). In order to analyze the changes and trends, we first extract several keywords in the political sections of four major newspapers which constitute the Trends 21 Corpus[2000-2009]. And then, by t-score analysis we extract the words related to the keywords. Once degrees of relatedness of words related to a keyword are measured by t-scores year by year, the increase or decrease of the relatedness of those words is analyzed first, by Mann-Kendall time-serial analysis and second, by regression analysis. We can summarize the changes of public interest in political situation in Korea as follows(through the years of 2000-2009). (a) Increase of the interest in ideology: "Jinbo"(the progressive), "Bosu"(the conservative), "Jungdo"(the middle), "Jwapa"(left wing), and "Upa"(right wing). (b) Changes of the interest in isms('-jueui'): Neo-liberalism, Liberalism, Pragmatism(increase) vs. Regionalism, Regional Emotion, Egoism, Authoritarianism(decrease). (c) Changes of the interest in political issues: Low-income class, Communication, Demonstration, Development(increase) vs. Reform, Corruption, Partisan(decrease). (d) Others: increase of the interest in Government, Constitutional Reform vs. decrease of the interest in North Korea, North Wind, Fairness