Ii Naosuke managed to coerce the Tokugawa shogunate to the last brief resurgence of its power and position in Japanese society before the start of the Meiji period.

[3] However, since Naosuke was the 14th son, he was not in line for a prominent position and was sent early in life to a Buddhist temple, where he lived on a small stipend from his family.

Fortunately for Ii, even though he was sent to the monastery, his 13 elder brothers were either adopted into other families who needed an heir, or died before they succeeded their father.

[7] Ii led the fudai daimyōs in their effort to bring about the downfall of Abe Masahiro and replace him with Hotta Masayoshi.

An intelligent and capable politician Ii Naosuke was determined to restore the power of the bakufu in Japanese policy making, both in a domestic and a foreign role.

Bakufu critics considered the treaties signed by Ii Naosuke to have seriously compromised Japan's sovereignty, and recovery of this power became the basis of a large part of the policies formed during the Meiji period.

As head councilor of the Tokugawa house Ii was now free to influence the decision in favor of whichever candidate he preferred without any interference.

In response to the attempt by Tokugawa Nariaki and his supporters to denounce him in the emperor's court Ii had a shogunal decree passed which allowed him to conduct the Ansei Purge.

Ii Naosuke was also able to remove officials who had expressed unhappiness with his handling of the Harris treaty and the shogunal succession from public life.

Kōbu gattai was a policy binding Kyoto and Edo closer together to shore up the failing shogunate with the prestige of the imperial court.

Prominent court official Konoe Tadahiro responded favorably to the proposal, insinuating a marriage between the shogun and Princess Kazunomiya was possible if her present engagement failed.

Ii's assassins were later granted a general amnesty by the bakufu, a precedent later used by Yamagata Aritomo, a key member of the Meiji restoration and a main architect of the military and political foundations of early modern Japan and Japanese militarism, to show that any action can be forgiven if it is performed for the betterment of the emperor.

Even his enemies would admit that, along with Tokugawa Nariaki, Ii was one of the most important political figures of the late Edo period of Japanese history.

Due to the often-tyrannical means Ii used to maintain his power, he was the subject of extremely negative press and was portrayed as a villain in much of the literature from his time, for example in the poems of Tsunada Tadayuki.

Historians such as Miyauchi and Beasley consider that Ii was nonetheless a patriot who carried out all of his acts in the belief that they were for the good of Japan and the Emperor.

On October 7, 2009, Ii Naotake, a family descendant of Naosuke, attended a memorial ceremony with the people of Fukui in reconciliation over the execution of Hashimoto Sanai in the Ansei Purge.