Short version? The economy is strong but deficits (including budget, social security, and Medicare) pose significant threats.
FRB: Testimony, Greenspan --Economic outlook and current fiscal issues-- March 2, 2005:
"I fear that we may have already committed more physical resources to the baby-boom generation in its retirement years than our economy has the capacity to deliver. If existing promises need to be changed, those changes should be made sooner rather than later. We owe future retirees as much time as possible to adjust their plans for work, saving, and retirement spending. They need to ensure that their personal resources, along with what they expect to receive from the government, will be sufficient to meet their retirement goals.Well said!
Addressing the government's own imbalances will require scrutiny of both spending and taxes. However, tax increases of sufficient dimension to deal with our looming fiscal problems arguably pose significant risks to economic growth and the revenue base."