I read on wikipedia :
The eleven murderers of Prime Minister Inukai were court-martialed; however, before the end of their trial a petition arrived at court containing over 350,000 signatures in blood, which had been signed by sympathizers around the country to plead for a lenient sentence. During the proceedings, the accused used the trial as a platform to proclaim their loyalty to the Emperor and to arouse popular sympathy by appealing for reforms of the government and economy. In addition to the petition, the court also received a request from eleven youths in Niigata, asking that they be executed in place of the Navy officers, and sending eleven severed fingers to the court as a gesture of their sincerity.
I find it hard to comprehend why people would go to such lengths to defend assassins of democratically elected leaders, can someone please shed some light on the background of the strong public support?
There's something I'd like clarify before answering.
Inukai was not elected democratically, his party was. Imperial Japanese Constitution is very vague about actually appointing a Prime minister. In fact, the original wording is only that "The emperor shall appoint ministers to assist him".
Slowly though, the actual process evolved to become that the house would recommend the majority leader to the emperor and the emperor usually would approve it.
Inukai was selected as the prime minister as the majority leader when his predecessor Wakatsuki resigned under the failure to reach a consensus in his cabinet facing the Manchuria incident. The then convention when the Prime minister disbands his cabinet and resign, as none of this was written in the Constitution, was to relinquish the control to the majority opposing party,
Once Inukai took the place of prime minister he immediately ordered the House to disperse and a new election to be held. His purpose was to use the popular support of his party "Rikken Seiyu Kai" and win the majority of the seats. His plan succeeded.
He immediately went ahead to attempt to deal with the 2 biggest concerns then. The economy, as the Great depression and the Kanto earthquake was having it's effect in Japan. And the Manchuria incident.
Unfortunately for him, he didn't really succeeded in both. His economic policy, although slowed down and stabilized the economy. Benefited the large financial cliques mostly, and this fact was not accepted by the majority of people. Public opinion become angry at the financial cliques, "big banks", who profited largely from the economic downturn and the government who helped them through policy.
On the other front with the Manchuria incident, Inukai refused to officially recognize Manchurian government. Although he was aligned with the military faction politically, he wanted to resolve this peacefully with the Chinese government. (He had some contact/friends in the Chinese government.) He sent a journalist to China to try to resolve the issue with them using unoffical channels. However, his Interior minister was a staunch anti-Chinese hardliner, and intercepted the unofficial channel communications.
And finally, he publicly expressed his worries about the young officers - those that just graduated from the academy - about their late actions. Namely the assassination attempts.
On one occasion he expressed his wish to dismiss about 30 officers directly to the emperor.
The military command, and the young officers and right-wing hardliners immediately jumped on this and called this a violation to the Commander-in-Cheif's(Emperor's) power, as the constitution only allows the Emperor to control the military, not the civilian government.
Ironically, Inukai himself used this very argument when he was leading the charge against the London Naval Treaty a couple years ago.
That marks his end of any sort of popularity and legitimate support. The death of Inukai marked the end of the Taisho democracy and the solidification of the military commands power. As now all politician had to watch out what they say in public in fear of assassination.