As with most other courtiers in Kyoto, Iwakura opposed the Tokugawa shogunate's plans to end Japan's national isolation policy and to open Japan to foreign countries. When Hotta Masayoshi, a "Rōjū" of the Tokugawa government came to Kyoto to obtain imperial permission to sign the Treaty of Amity and Commerce (United States–Japan) in 1858, Iwakura gathered courtiers who opposed the treaty and attempted to hinder negotiations between the Shōgun and the Court. The imperial court and shogunate had a conflict because of the Treaty of Amity and Commerce. The shogunate agreed to sign the treaty, but almost the people of the imperial court had the opposite idea. However, Kujō Hisatada, an authority of the imperial court, supported the shogunate's idea. Iwakura wanted to prevent the treaty of Amity and Commerce, so he decided to use an unusual method. In particular, he planned to have a direct talk with the "Kanpaku" by leading a lot of nobles. As a result of this, the "Kanpaku" agreed to prevent signing the treaty. This incident is called the demo of eighty-eight retainers of the Imperial court, and it made Iwakura famous. Two days later of the incident, Iwakura wrote a political written opinion. It was said that he wanted to postpone signing the treaty because he thought Japan needed to learn about the situation and customs of foreign countries. Also, he emphasized domestic consensus in the written opinion. In 1858, Ii Naosuke became Tairō and signed the Treaty of Amity and Commerce without asking the emperor Kōmei. This angered the emperor, and the relationships between the imperial court and the shogunate became worse. Iwakura made an effort to find a way to settle peacefully.