Checkbook Politics in US

As the Amazon rating, Kensuke Karube, a corespondent in the Jiji Press, tells the mechanism of the money politics in the Unites States very well. I could understand the systematic and legal methodologies of the money politics in USA.
As you know, Lobbyists are very important and major positions in the politics. In addition, political action committee (PAC) is also very important to gather money.. It seems the Noukyo in Japan.
However, there are a large gap between Japan and US on thoughts of money in politics. It's not banned in USA, but the Japanese dislikes to support politicians with money...