This is from an article that ProPublica just published:
The most prominent and frequent traveler appears to have been the American Enterprise Institute’s Fred Kagan. Best known as the intellectual author of the Iraq surge strategy, Kagan said he and his wife, Kimberley Kagan
of the Institute for the Study of War, spent a total of about 270 days
in Afghanistan while Petraeus was in command from summer 2010 to summer
2011, and about 128 days under Gen. John Allen, who took command after Petraeus and remains in the position.
Like others we spoke with, Kagan said Petraeus and other generals have
routinely brought think tankers to both Iraq and Afghanistan, both to
solicit outside advice and to shape the debate back home.
Defense Department spokesman Bill Speaks told ProPublica that the
Pentagon often reaches out to such outside experts to advise war
commanders.
“We do periodically invite those experts involved in relevant
research to receive briefings on the status of the campaign,” Speaks
said in an email. He said the military does not have a comprehensive
list of think tank members who have visited the U.S. headquarters in
Kabul.
Indeed, the trips do not appear to have been part of any formal program, and they often differed in length and purpose.
Other think tankers we spoke with say they spent much less time in
Afghanistan than Kagan, usually a few weeks or less. Those who have
participated are from both Republican- and Democratic-leaning think
tanks and they said they were not compensated.
“We did battlefield circulation, visited units in the field, and met with local political and security leaders,” says John Nagl,
a retired Army officer and current fellow at the Center for a New
American Security who took one military trip to Iraq and two to
Afghanistan.
Nagl — who said attendees were responsible for getting to Kabul on
their own and the military then covered transportation, lodging, and
food — believed the trips allowed him “to be better informed in my
analysis and advocacy.”
Michael O’Hanlon
of the Brookings Institution, who has taken the trips several times to
both Iraq and Afghanistan, says the practice first became common under
Petraeus during the surge in Iraq in 2007.
Kenneth Pollack, also of Brookings, credits a 2007 military trip to Iraq with prompting he and O’Hanlon to write an influential New York Times op-ed supporting Petraeus’ surge strategy in the country.
“I hesitate to say these trips are uniformly good or bad. They can be
both, they can be neither,” Pollack told us. “It so depends on the
people you meet and the people you’re taking” on the trip. At times
“there’s no question they’re trying to have you see things the way that
they see them. But if you’re smart about it, you can get past that.”
Max Boot, a fellow at the Council on Foreign Relations, has also gone on the trips. He declined to comment.
Here is a previous Think Tank Watch post on David Petraeus's connection to think tanks.