The globalization of capitalism affects politics in most of the countries that are touched by this trend. Countries have to adapt to the changing demands being made on them and their people. This changes the political dynamics of those countries.
For example, in the US, globalization affects our politics by making many Americans skeptical about trade, particularly with China. Mitt Romney, who may well be the next president of the US, says that he will declare China to be a currency manipulator (basically saying that they cheat to help themselves export goods) on his first day as president. Because globalization has changed the sorts of jobs that are available to Americans, it impacts our politics.
Globalization changes the pressures on all the countries it touches. It also makes every countries' affairs affect other countries in some way. For these reasons, it is related to politics.