参議院さんぎいん選挙せんきょ 国民こくみんと参政さんせいが躍進やくしん 背景はいけいには“戦略せんりゃく的てきなSNS活用かつよう”

In this House of Councillors election, the Democratic Party for the People and the Sanseito Party significantly increased their seats.

We thoroughly interviewed the voices of supporters and, together with experts, analyzed the social media platforms that both parties are focusing on.

What was behind the growing support that emerged from there?

So I went around asking the people who had gathered there why they supported him.

The trigger was YouTube or social media. When I asked people who came to listen to these speeches how they learned about the Sansei Party, most of them mentioned YouTube or social media.

He is a man in his 40s from Nishitokyo City, Tokyo, whom I met at the speech venue.

Up until now, you say you didnt have a particular political party you supported—in other words, you were part of the so-called independent voters—but this time, videos on X and YouTube led you to support the Sanseitō party.

He said that he spreads information on his own X account by quoting statements from Sanseitō or those with similar views to the party.

After seeing the content posted on X and their political policies, I felt that I wanted to entrust things to these people.

I resonated with the fact that they put Japanese people first.

Mr. Sagawa, who has been posting videos related to politics, such as explanations of elections and international affairs, for about five years.

I have over 100,000 followers, and in addition to YouTube, this time I also posted on TikTok.

On the final day of the election campaign, the last appeal by the Sansei Party, held in Minato Ward, Tokyo, was streamed live.

At the start, there were about 30 viewers, but during the roughly two-hour stream, the number temporarily exceeded 1,500.

As a result, 209 out of 210 people, except for one, owned at least one social media account, and about 93%, or 194 people, had posted themselves or shared posts supporting the Sanseito partys policies or support at least once, meaning that every member actively used social media to share information.

Many of the widely shared posts and content were quotes from Representative Kamiyas posts or announcements of street speeches by candidates from various regions.

On the Saturday before the election, when we spoke to people who had gathered to listen to street speeches by Representative Tamaki, Secretary-General Shinba, and others, many said they resonated with policies that focus on the working generation, such as increasing take-home pay.

I also think its good that they are listening to young peoples voices and that the message is solution over confrontation.

I work part-time at a restaurant, and I think it would be nice to be able to work without worrying about the income cap, since I can expect to earn more.

After studying on my own this time, I felt that the Democratic Party for the People made the most sense to me and I wanted to support them, so I decided to participate as a volunteer.

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There are at least about 8,000 videos related to the Sanseito party, and they have been viewed more than 375 million times.

For all parties, the videos with the most views were those edited by third parties, featuring politicians statements or street speeches.

However, since the Tokyo Metropolitan Assembly election held in June, a noticeable decline in views has been observed, and as of the 18th of July, the number of views was just over 23 million.

On the other hand, the Sanseitō

Originally, most of the content was posted by the party’s official channel or its supporters, but from around May 2025, more clip videos began to appear. By June, the number of related video views had surpassed the Democratic Party for the People, reaching nearly 97 million, and as of July 18, it had reached 155 million.

There were especially many videos related to the Sanseito party that were clips from their speeches during the House of Councillors election, while the number of videos critical of the Sanseito party, as well as videos by TV stations and online media, was also increasing.

Some channels that originally posted edited videos of the Democratic Party for the People changed their content during the House of Councillors election period and mainly started posting videos of the Sanseitō party; there were several such cases.

We asked Professor Fujio Toriumi of the University of Tokyo, who is well-versed in SNS analysis.

On the other hand, the Sanseito party had around 40,000 members in March, but this month it has reached nearly 90,000, making it the highest.

Furthermore, when looking closely at the accounts spreading information about the Sanseito party as of mid-this month, it was found that as of March this year, about 20% had been sharing posts related to the Democratic Party for the People, while more than half had not been spreading information about any political party. Professor Toriumi pointed out, It is highly likely that a considerable number of people who were not very interested in politics have joined.

Professor Toriumi analyzes that the background of this situation is that know-how has been accumulated through the use of SNS and YouTube videos in election campaigns, such as the House of Councillors election three years ago, last years Tokyo gubernatorial election, House of Representatives election, and Hyogo gubernatorial election, and that this know-how is now being used in the current House of Councillors election as well.

On the other hand, it was pointed out that one should be aware that, due to the nature of social media, content that attracts attention is displayed preferentially and directly linked to income in the attention economy system, that there are people who try to attract interest with sensational or sometimes false information, and that on platforms like YouTube, AI recommendation systems tend to show only similar content, such as information about the first political party you watched, making it harder to access different perspectives.

For example, measures such as prohibiting monetization of election-related videos during the election period are being implemented in other countries as well, and by doing so, it may be possible to create a somewhat healthier information environment.