Japan has been trying to stimulate its economy for 15 years, with mixed results. A sudden collapse in the exports has brought calls for more. The current plan: a five trilion yen ($50 billion) package, the biggest part of which is a cash giveaway to families. That's just 1% of GDP, but after years of big deficits, there are limits to what Japan can do. Infrastructure spending is actually down from the high levels of the 1990s.