Liquidity Trap is a euphemism for institution carrying irresponsible loans who don’t want to go bankrupt. They seek to be rescued (with your savings) from the dreaded liquidity trap. It is at the heart of Keynesianism.
They say there isn’t enough money. People will stop spending. When people stop spending, businesses will go under. When businesses go under, more people will be out of work. And so on in a vicious, self-reinforcing spiral.
This Mises daily article helped me understand the nonsense of this idea, which Keynesians discuss with much subtelty: http://mises.org/daily/3697
Here’s my short version.
The only time people will stop spending altogether is when they no long want goods and services provided by others. In other words, never.
Price fluctuation can absorb any amount of hording of cash. If people are filling their mattresses with dollars, prices will simply drop. Opportunities will be created for those who choose to buy things.
Most people will save their money in banks. If we lived in a free society, and the interested rate was settled on the free market, the increased savings would create more opportunities for people who want to borrow money. This would be manifest in low interest rates.
High savings create lots of opportunities to borrow and thus low interest rates. Low savings make it hard to borrow and thus high interest rate.
One very important, uniquely Austrian point, is that this harmonizes savings with interest rates. It harmonizes future planning of people (who are saving) with opportunities for entrepreneurs to begin long-term projects.
Keynesianism treats all production equally — long term, short term, building computers, digging ditches — as if humans produced and traded blobs of meaningless GDP. The Austrians identify short and long production processes and their need to be harmonized with savings (which reflect whether people are planning for the short or long term). This distinction gets messed up with the Fed sets the interest rate or rescues institutions from the so-called “Liquidity Trap.”