The last time the US embarked on a major war in the Middle East, in 1990, the legacy included a generation of veterans who were victims of Gulf War Syndrome, and who had to wage a long fight against bureaucracy to get their disease officially acknowledged.
Now some fear the latest US war there is also leaving a generation of veterans sick in ways they will have to fight to get recognized and treated for.
Gulf War Syndrome - a complex collection of symptoms typically including some combination of chronic headaches, difficulties understanding and communicating, widespread pain, unexplained fatigue, chronic diarrhea, skin rashes and respiratory problems - began to strike US servicemen and women before Gulf War One was even over.
And yet it took years before the US government would even acknowledge the existence of the disease - and it still is not doing enough to study the condition, according to a recent report by the Research Advisory Committee on Gulf War Veterans' Illnesses, a congressionally mandated blue-ribbon panel appointed by the Bush administration in 2002. The committee concluded that between one-quarter and one-third of the 700,000 US troops deployed - as many as 210,000 veterans - are affected by the disease to some extent.
"No effective treatments have been identified for Gulf War illness and studies indicate that few veterans have recovered over time," adds the report.
The scientific experts on the advisory committee surveyed the research literature, about 1,800 studies, and concluded "evidence strongly and consistently indicates" Gulf war Syndrome was caused by exposure to neurotoxins - poisons that attack the brain and nervous system - in pesticides troops used and special experimental pills they were made to take, designed to protect against the effects of nerve gas.
Anthony Hardie, a Gulf War veteran and advocate and a lay member of the advisory committee, told the left-wing radio news program Democracy Now! that troops had to be ordered to take the pills, because the side-effects were well known.
"We were mandated to take the pills," he said, adding, "I was required to physically watch my soldiers put the pill into their mouth, swallow it and make sure that they had taken it ... these measures were taken because there were significant side effects for so many of us."
"About two-thirds of the group that I was with began to be ill from the pyridostigmine bromide, or the nerve agent protective pills that we took, and then, once in Kuwait, began having severe respiratory and sinus issues," Hardie said.
The advisory committee noted "the consistent association of Gulf War (Syndrome) with PB and pesticides across studies of Gulf War veterans, identified dose-response effects, and research findings in other populations and in animal models" as the basis for their conclusion.
The report also said there were several other possible causes - including low-level exposure to nerve agents, close proximity to oil well fires, and receipt of multiple vaccines - where "evidence (of causal association) is inconsistent or limited in important ways."
Sick veterans faced years of official denials, said Hardie, and the report suggests that they are still battling an indifferent administration, noting that the Pentagon cut funding for research into Gulf War Syndrome from US$30 million in 2001 to less than US$5 million in 2006.
The committee called for research funding to be boosted to at least US$60 million a year.
"This is a national obligation, made especially urgent by the many years that Gulf War veterans have waited for answers and assistance," the committee said.
But now, there are fears that a new generation of veterans will face similar official indifference to a new generation of disabling conditions resulting from the unique conditions of their own conflict.
In the case of these veterans of the wars in Iraq and Afghanistan, the "invisible wounds" are Traumatic Brain Injury (TBI) and Post-Traumatic Stress Disorder (PTSD) and other stress-related conditions.
TBI - which varies from severe "open head" wounds to the mild blast effects described by experts as a kind of "whiplash of the brain" - is especially prevalent in Iraq and Afghanistan because of the types of blast injuries troops get inside armored vehicles attacked by roadside bombs or other explosives.
These injuries are often the result of blasts that do not strike the head directly, and leave no visible signs in the case of "closed head" wounds. Some TBI symptoms are easily confused with stress disorders or with other common syndromes experienced by troops, like sleep deprivation.
As a result, they may be under-diagnosed and too little is known about them, says a new report from the US Institute of Medicine.
The long-term effects even of moderate TBI can include Alzheimer's-like dementia, aggression, memory loss, depression and symptoms similar to those of Parkinson's disease, the report found.
"We are seeing much higher rates of non-penetrating traumatic brain injury and blast-induced injury among military personnel who have served in these countries than in earlier wars," said the chair of the Institute of Medicine committee that wrote the report, George Rutherford, professor of epidemiology and preventive medicine at the University of California School of Medicine in San Francisco.
As of January, more than 5,500 military personnel have been diagnosed with TBI during the conflicts in Iraq and Afghanistan, according to Pentagon figures cited by the institute, and some studies indicate that as many as one-in-five of all combat casualties in the two theaters suffer TBI.
The institute called for long-term research including large-scale cognitive testing of troops pre- and post-deployment to better evaluate and respond to TBI.
As to stress-related illnesses, a study earlier this year by the RAND Corporation, a think tank with historic ties to the US military, revealed a mental health epidemic among service-members and veterans. It estimated one-in-five US personnel currently or previously in Iraq and Afghanistan are suffering from mental health problems, including PTSD, the study found - a total of 300,000.
The relentless pace of deployments in both theaters has added to stress on the troops, acknowledged Chairman of the Joint Chiefs of Staff Admiral Michael Mullen, in an interview last week with the Associated Press.
"We see extraordinary stress and pressure there," he said, referring to the many US troops who have now done multiple year-long deployments.
The advocacy group Veterans for America says that Department of Defense studies show troops are 60 percent more likely to develop post-combat mental health problems with each deployment.
The result is a huge challenge for President-elect Barack Obama's new pick to run the huge Department of Veterans Affairs, General Eric Shinseki.
"The system of care designed to treat post-combat mental health injuries, the most common wounds of our current wars, is inadequate to the task and will be for the foreseeable future," Veterans for America said in a recent report.
Shinseki briefly acknowledged the plight of TBI and PTSD sufferers when Obama officially named him Sunday. "Veterans who have served in Iraq and Afghanistan in particular are confronting serious severe wounds - some seen, some unseen - making it difficult for them to get on with their lives in this struggling economy," he said.
Seventeen years after coming home, Gulf War veterans sickened because they followed orders still face an obstructive and obfuscating bureaucracy. Current Veterans Affairs Secretary James Peake has referred the Gulf War Syndrome report to the Institute of Medicine for further study.
If Shinseki really wants to repay the "national obligation" the US owes these men and women, he could make a start by ensuring that their struggle does not have to repeated by a new generation of sick veterans.