How do you define "Quagmire"?

My conservative friend Alamo City Commando observes in the comments to the previous post that "liberals in this country think Iraq is a quagmire while the Iraqis are happy to be free."
To that I would respond what difference does it make what some Iraqi's think? (And I do mean some since it is obvious there are still quite a few who are not happy that we are over there.)
There were quite a few Vietnamese who were happy when we were controlling Saigon and very unhappy after we left. But that did not make the Vietnam War any less of a quagmire.

How do we define quagmire anyway?
It would be interesting to know what definition conservatives would have used prior to the war.

Back then, the Bush administration was arguing that the conflict would be settled in a matter of months if not weeks.
Now, we are past the two-year anniversary with still no end in sight.

Back then, the Bush administration was reassuring us that U.S. casualties would be few - possibly along the lines of the first Gulf War, if that many.
Now, we have passed the 1,500 mark for U.S. military fatalities and 11,000 wounded, and still with no end in sight.

Back then, the Bush administration was telling us the cost of the war would be negligible and would be recouped with Iraqi oil revenues. Larry Lindsey, the president's top economic advisor, was forced to step down for suggesting that the cost could rise to as much as $100 billion.
Now, the cost to U.S. taxpayers has exceeded $300 billion with no end in sight.

So I'll ask again. How do we define quagmire?
Let's recap: We've been there for two years, spent $300 billion and lost 1,500 U.S. troops and the Iraqi government is still so weak that it would collapse like a house of cards if we were to even suggest pulling out in the next six months.
If it had been suggested prior to the start of the war that this would have been the cost and the end result - is there any question that the vast majority of U.S. citizens would have joined the rest of the world in condemning this unprecedented pre-emptive invasion to search for non-existent WMDs?