History of our 21st century wars will be difficult to write

That's because there is a dearth of records that have been normally kept by those fighting all of our wars going back centuries.  This has at least two deleterious consequences: veterans have a hard time proving they are entitled to benefits and it makes it harder for military strategists to learn the necessary lessons from Iraq and Afghanistan. 

It's not as though the Pentagon did not know the problem was building.  It occurred in the Gulf War of 1990-1991; we spent years and millions of dollars to reconstruct the locations of troops who may have been exposed to toxic plumes that were among the suspected causes of Gulf War Syndrome.   In 2005 the Pentagon learned of the same record-keeping problem in the Iraq and Afghanistan Wars.  While the bosses may have issued commands to collect and preserve records, little was done in the field to implement these commands.