In this post I wondered why Japan didn't experience a classic overinvestment slump and recovery normally seen in the years preceding WWII.

Via Joe Wiesenthal, Richard Koo, economist for Nomura writes:

Arguing need for longer-term fiscal consolidation is irresponsible
The insistence that fiscal consolidation is necessary in the longer term is like the doctor who, faced with a patient who has just been admitted to the intensive care ward, repeatedly questions the patient about his ability to afford the treatment. This is both lacking in decency and irresponsible.

If the patient loses heart after learning the cost of the treatment, he may end up spending even longer in the hospital, leading to a larger final bill. Completely ignoring the policy duration effect of fiscal policy and constantly insisting on longer-term fiscal consolidation was what prolonged Japan’s recession.

For instance, it was because Japan’s policymakers refused to give up the medium-term fiscal consolidation target of achieving a primary fiscal balance by 2011 that the government stumbled from fiscal stimulus to fiscal retrenchment and back again and, ultimately, was unable to meet its fiscal targets even once in the last 20 years.

That is why Japan’s recession lasted as long as it did and why the nation’s debt has risen to some 200% of GDP.