The Japanese government limits the number of days you can campaign, it limits the number of speeches you can give, the types of places you can speak, and the number of handbills and bumper stickers you can print. And it limits each candidate to one megaphone. The Japanese government has effectively slashed the cost of campaigning. But it has also made it extremely difficult for opponents to make their cases against incumbents. The leading party in Japan has ruled that country for all but about three of the last 55 years.
Polls show the governing party is unpopular.
But when election time comes, the opposition is restricted in its ability to make its case. I don't think we want to imitate that approach. But, nobody's talking about such a high level of regulation in American elections. We're just talking here about restricting campaign donations. The most important task of political parties is to help opponents against incumbents.