[1] In 2006, he applied for the Liberal Democratic Party’s open recruitment for a by-election in Chiba’s 7th district for the House of Representatives.

delivered by LDP Secretary General Tsutomu Takebe and others gained significant attention, but Saito was defeated by a narrow margin of 955 votes by Kazumi Ota of the Democratic Party of Japan.

Saito was at the forefront of advancing a revised immigration law, which sought to overhaul the asylum process.

The revision was opposed by the CDP, which submitted a censure motion against Saito on 6 June 2023 in order to delay it.

Saito oversaw the expansion of Japan's semiconductor industry, through government subsidies to companies.

He withdrew on September 11, having been unable to gather the twenty diet members necessary to be nominated.