1. Rise of the Parties
Since the Meiji Restoration, civilian bureaucrats and the military had ruled
Japan in the name of the soverign emperor. The constitution of 1889 served
to confirm the centrality of the monrchy and the bureaucracy, but the the
Japanese people were given a tiny window, a limited voice to affect policy
decisions through the elected lower house of the Diet. However, Ito Hirobumi,
who drafted the constitution, expected that bureaucrats and generals would
continue to rule without sigificant accountability to the broader populace.
Things turned out differently than anticipated. The Diet actually became a
site of contestation in which the leadership group's authority was significantly
challenged from time to time. A vigorous drive for participatory parliamentary
politics emerged first as the Seiyukai was formed and functioned as a party
whose leader (Saoinji) alternated the Premiership with a representative of
the Oligarchs, Katsura Taro, between 1905-1913, and then, even more so, when
a second party emerged.
This came about with the "Taisho" political crisis of 1912, when
a second party, the Doshikai, was formed and it evolved into the KENSEIKAI
and later the MINSEITO. It turned out to offer a vigorous, liberal challenge
to the Seiyukai. So during the years 1918-1932 there was a "Normal"
sharing of power between the heads of these 2 political parties so it is sometimes
referred to as "the era of normal constitutional government." These developments suggested to observers and historians that trends were moving inexorably in the direction of more participation by popular forces and voices in the Meiji Consitutional framework.
2. International Influences--Wilsonianism, Allied Vistory WWI, world made
safe for democracy, ideal of national self-determination for all nations, etc.
3. Minobe Tatsukichi's Organ Theory of Constitutional Monarchy--helped provide a legal framework in which the monarch could be seen as one"organ" within the polity along with other "organs" like the Diet, the Bureaucracy--civilian and military--the Cabinet, the Political Parties, etc. His view held sway for over 32 years and he was honored throughout the country and he was even appointed to a seat in the Upper House of Japan's Diet.
Minobe held that the emperor was an organ of the state; the repository of sovereignty, he was still a constituent part of the larger entity, the state. Hozumi Yatsuka (1860-1912) and Uesugi Shinkichi (1878-1929), both also professorsion the University of Tokyo Faculty of Law, provided the theoretical underpinning for an alternate doctrine. Citing conservative European legal theorists (and paraphrasing France’s Louis XIV), they argued that the emperor was the state. The two positions framed the legal debate under the Meiji Constitution. - See more at: http://www.japanfocus.org/-richard-minear/3904#sthash.Kggn16in.dpuf
4. Yoshino Sakuzo's liberalism, minponshugi v. minshushugi = also helped provide a framework rooted in political phislophy tht could support "democracy" and popular particiaption in prewar Japan.
民本主儀 民主主義
A Christian with sympathies towards socialism, Yoshino tried to make the
notion of democracy and popular sovereignty compatible with the emperor
system by coining Minponshugi phrase. He was central to the student organization, the Shinjinkai or New Man Society. It's goal was to "advance the new trend towards the liberation of humankind" and a aimed to bring about the rational reform of contemporary Japan (1918).
Yoshino combines liberalism at home with voice for self-determination
for colonial subjects, especially Koreans.
Along with Shimada Saburo, he criticized military interventionism and
arms build-up of Seiyukai.
He advocated universal manhood suffrage, civilian control over the military,
the transformation of the House of Peers to a popularly elected body, and
an active social welfare program. He believed that over time the imperial institution would be stripped of its magical aura the way primitive conception sof Jehovah had been. He saw the emperor as a human and civil monarch.
In the end, he would come to see the parties as "entrenched"
elites who were corrupted and catered only to private, selfish interests
of the large economic combines, the Zaibatsu.