My opinion on the matter is that ultimately this is a maneuver to devalue the dollar. Historically, there are two ways out of massive sovereign debt: 1) default, and 2) print as much currency as you can so that you can easily pay your debts with worthless paper (or coin as it has been historically).

This is a method under the guise of helping the housing market to inject billions (if not trillions) of extra liquidity. Eventually, that leads to higher inflation, which devalues the currency.