A lot of people are asking why high unemployment, a lagging indicator in a recession, has this time around stayed so high for so long. Some blame the cyclical nature of downturns. Some blame globalization-since workers are cheaper overseas and more attractive to companies slimming down as they come out of market slumps. But there are demographic issues and structural issues harming U.S. employment this time around, says Brian Gendreau, professor of finance at the University of Florida and a market strategist at Financial Network.

"There are structural forces in play," Gendreau says, "which is bad news because these are really somewhat more intractable than just reducing unemployment through stimulating the economy. A lot of the unemployment is concentrated in manufacturing and construction. Those are industries that were very hard hit in the last recession. And retraining those workers is very difficult. It's very hard for a worker in manufacturing and construction to become an X-ray technician."

Other structural problems, he says, are Americans' hampered mobility. In the past, they could move to find work. But now they are stuck in houses they can't sell because of the residential home glut. Others see structural problems in extended unemployment benefits, which they argue discourage people from seeking work.

Or it could be that the problems this time are different simply because this recession wasn't like others, but instead was caused by leveraging at every level of the economy-debts that are going to take a long time to unwind. Erik Weisman, an economist and portfolio manager at MFS Investment Management, points to studies by Carmen Reinhart and Kenneth Rogoff suggesting that we are only in the middle of the recovery, because it could take as much time to unwind leverage as it did to build it up. The previous two recessions in the U.S., he says, were mild, and didn't open up a big output gap. There was not a lot of excess capacity and excess labor as there is now.

"There's a great symmetry in that," he says. "You can make an argument that time zero is 2002, in which case it's a five-year bubble and it should take five years to unwind. Maybe it's 1997, in which case it's ten years. Maybe it's 1987. We don't know the answer. But what I do feel pretty comfortable with is the notion that we are only in the sixth quarter of this recovery. The ramifications from this recovery will be felt for several more years."

Weisman points to the 1960s and 1970s as years when the leverage in the system was less and when monthly seasonally adjusted nonfarm payrolls rose at a steady rate of 3% per year or so. In the 1980s, he says, those trends reversed: Debt to GDP started to increase, and at the same time, labor and GDP growth both started to see negative downward trend lines. Though he says there's not a correlation, per se, the trends might be associated.

"My supposition would be that in the '50s, '60s and '70s, if you had a good investment idea ... and you're not levering that thing up, it's got to be a good idea. You need labor and capital for that idea to work. As we're able to lever these things up, you can now come up with bad ideas that maybe will only give you a 1% to 2% return. Levered up ten times, now it's a great idea. But you sure don't need a lot of labor and capital to do that."

He says he's waiting to see if deleveraging results in better investment opportunities.

Is there any reason for optimism for the economy otherwise? If so, it might be overseas.

"The emerging market looks pretty good," says Gendreau. "Latin America is growing at rates it hasn't seen in a generation. I don't see anything that would derail that in 2011. So that story is intact." Though some countries like India and China are trying to slow their growth a bit, which will affect the U.S., those same countries are still going to be seeing increased demand, and the U.S. has a good chance of participating in that.