"The chance of hundreds if not thousands of US soldiers dying in Iraq on the current course is about 100%.

The chance of thousands if not tens of thousands of Iraqi civilians dying in Iraq on the current course is about 100%.

The chance of many billions of US dollars being spent in Iraq on the current course is about 100%.

The chance of thousands if not tens of thousands of US soldiers being maimed and disfigured in Iraq on the current course is about 100%.

How do you define "success" again? "

"There are more than 970,500 sworn law enforcement officers now serving in the United States, which is the highest figure ever. About 11.6 percent of those are female.
...
A total of 1,635 law enforcement officers died in the line of duty during the past 10 years, an average of one death every 53.5 hours or 163 per year. There were 155 law enforcement officers killed in 2005. "
http://www.nleomf.org/TheMemorial/Facts/history.htm

So that's in police officers killed while on the clock. Some more from above link:

"On average, more than 56,000 law enforcement officers are assaulted each year, resulting in over 16,000 injuries.

The 1970s were the deadliest decade in law enforcement history, when a total of 2,260 officers died, or an average of 226 each year. The deadliest year in law enforcement history was 1974, when 275 officers were killed. That figure dropped dramatically in the 1990s, to an average of 159 per year.

The deadliest day in law enforcement history was September 11, 2001, when 72 officers were killed while responding to the terrorist attacks on America.

New York City has lost more officers in the line of duty than any other department, with 686 deaths. California has lost 1,401 officers, more than any other state. The state with the fewest deaths is Vermont, with 19."

Obviously the situation in Iraq is more violent than America- that is not my point. My point is you can't expect no deaths or really low death rates say like Vermont. If the security situation ever got as good as New York or LA, we simply wouldn't have the need to be in Iraq. The question as far as success goes is measurable by how capable is the Iraqi security forces in handling the security- and the amount of deaths of security personnel or "citizens" should not be a metric in deciding when you want to run away or give up. Instead there are a number of factors and the most significant question is what is the consequences if the Coalition were to leave Iraq within a short period of time [less than 6 months as example]. I submit that we don't have a high confidence of knowing the result and the possibility that Iraq could have a civil war like the one the occurred in Lebanon for decades or in Afghanistan after the Soviet Union was defeated [which more less continued until the time we invaded Afghanistan in 2001].