The U.S. military sent a giant C-17 cargo plane to an air show in China this week as a way to strengthen its relationship with the People’s Liberation Army there, despite fears among security and policy experts that doing so puts American technology secrets in jeopardy and also risks angering an important Asia ally.

The decision to send a Boeing C-17 Globemaster III to the China International Aviation and Aerospace Exhibition at the Zhuhai Jinwan airport starting Tuesday is fraught for a number of reasons, defense and security officials told Defense One, noting that President Barack Obama’s arrival in the region this week to help bolster ties with Beijing points up how political factors may have outweighed security, optical and even legal concerns.

The reasons against sending the plane seemed to policy and security officials to have been enumerable. The American military jet will be participating in the air show with just two other foreign militaries in addition to China: the United Arab Emirates and Russia - with which the U.S. military severed ties after Russia’s annexation of Crimea this spring .

In the meantime, to some, the U.S. military’s participation in the air show is a mark of hypocrisy: Last week, the U.S. denied ally South Korea the ability to demonstrate a Korean jet at the same air show because it possesses U.S. technology and U.S. security officials said demonstrating that plane would be in violation of international agreements.

And at a cost of at least $350,000 to attend the air show, some officials inside the U.S. government raised questions about why the C-17 jet, along with about 15 U.S. Air Force personnel, should participate at all.

“It was just bad idea after bad idea,” said one government official.

But despite the myriad concerns, Pentagon officials recognized they were in a tight spot and signed off on the plan late Friday to avoid risking political fallout just as the president’s plane was about to touch down in Beijing.

Many U.S. government officials said that when it comes to reciprocity, the Chinese never deliver.

The decision to send the C-17 to the air show, which begins Tuesday, appeared to originate from U.S. Pacific Air Forces, or PACAF, as a way to engage the Chinese and strengthen the relationship between the two militaries. The idea was said to have been the brainchild of senior Air Force leaders in Washington and Hawaii, but few government officials in Washington knew about it until just weeks ago. One defense official joked that the event was a “GOBI” – a “General Officer Bright Idea” – because it went forward despite the mounting concerns with the plan.

Given the cost, the political optics and what some officials termed a borderline legal justification for participating, a variety of defense officials demurred when asked about the jet participating in the air show. The plan was considered such an “ugly baby” within the U.S. military that no department or agency seemed to want to take responsibility for it. Over the course of last week, Pacific Air Forces referred questions to the U.S. Air Force at the Pentagon; the Air Force referred questions to U.S. Pacific Command in Hawaii. The public affairs office at the Pentagon’s Office of the Secretary of Defense referred questions back to Pacific Air Forces, also in Hawaii. Ultimately a spokesman for the Air Force acknowledged the C-17’s participation in the show, saying it was coming “at the request of the government of China.”

Lt. Col. Christopher Karns, media operations chief for the U.S. Air Force at the Pentagon, said the C-17’s visit to the air show has a humanitarian assistance aspect to it, citing a statistic that nearly 70 percent of the world’s natural disasters occur in the region.

“Sending the C-17 builds trust and strengthens partnerships with China and Asia-Pacific nations,” he said. “The C-17 signals the Air Force’s capability to deliver humanitarian assistance and disaster relief through the Asia-Pacific region and across the globe,” he said in an email.

Justifying its participation in the air show by framing it as a humanitarian relief operation was significant because “mil-to-mil” engagement with the Chinese is extremely limited based on a law passed in 2000. Indeed, provisions of the 2000 National Defense Authorization Act prevent the U.S. from certain kinds of sharing or demonstrating military technology with the Chinese. But there is one exception: when humanitarian relief operations are involved. Policy officials concerned that the C-17 visit to the air show have expressed doubt that the true purpose of the C-17’s presence at the air show could be truly justified by being related to a humanitarian operation.

There is also political risk in the decision to send the plane as well since it came after last week’s decision to prevent South Korea from sending a Korean-made T-50 jet to the same air show. The South Korean T-50 is a training plane that incorporates American fighter technology that is similar to some of what is found on an American F-16 fighter. U.S. regulations prevent allies from sharing certain “munitions technology” or military capabilities and U.S. officials told the Republic of Korea they could not take the jet to the same Chinese air show. That ruling angered Seoul earlier this month, making the U.S. decision to send its own jet to the same air show appear that much worse to the South Koreans.

U.S. officials said that despite the action against South Korea, the decision to send the American jet to China was made carefully.

“Upon careful review of the International Traffic in Arms Regulations requirements and an assessment of the opportunity to strengthen engagement and ties with China, the State Department and the Office of the Secretary of Defense approved the participation of the C-17 at the [China air show],” a DoD official said in a statement to Defense One.

The Pentagon has long been suspicious of China and the People’s Liberation Army, or PLA, which U.S. officials have accused of lacking transparency and stealing military secrets from the U.S.

Despite those concerns, many U.S. officials think engaging with the Chinese military in the form of information exchanges or air shows or official visits are all worth it because they help build trust and, theoretically, a reciprocal relationship in which one military shows off its capability in return for more transparency from the other side. But many U.S. government officials said that when it comes to reciprocity, the Chinese never deliver.

Some members of Congress agree. Rep. Randy Forbes, R-Va., who has voiced his concerns on this issue in the past, said U.S. officials justify such exchanges as building relationships, but there’s little evidence the strategy ever pays off.

The Pentagon has long been suspicious of China and the People’s Liberation Army, or PLA, which U.S. officials have accused of lacking transparency and stealing military secrets from the U.S.

“It should be no surprise to us when the Chinese agree to attend the prestigious RIMPAC exercise or host a C-17 at their airshow, but we let ourselves interpret these actions as the basis for a new level of cooperation,” Forbes told Defense One in a statement by email, referring to the C-17 visit as well as a large Pacific military exercise in which the Chinese participated this year. “There is also no indication that more engagement has helped to shape Beijing's behavior. As we have increased our mil-mil outreach in the last 18 months, China has only turned more coercive and reckless.”

Forbes, a member of the House Armed Services Committee, said it’s important to “continue to engage” the PLA but there should be “clear guidance” across the Defense Department to make sure a set of objectives are being met.

There are regular reminders of the risk involved with the Chinese, they say. In August, a Chinese man was indicted for assisting two China-based hackers and other defense contractors to steal data on military jets, including Boeing’s C-17. And Su Bin, a Chinese national who owned a Chinese aviation firm, was indicted after first being arrested in June in Canada. He apparently spent years stealing secrets from Boeing, but it was unclear how he did so, according to The New York Times. There was no indication that the Chinese government was involved.

The U.S.-China military relationship is marked by ups and downs. Also in August, a Chinese air commander directed a Chinese jet to harass an American spy plane operating over international waters, “buzzing” the American jet and conducting what’s known as a barrel roll around it in an incident that could have caused a serious air crash.

Security and military experts fear that even just bringing the C-17 jet into China for the air show runs the risk that the Chinese could exploit its visit on the tarmac or inside a hangar at the air show by photographing the inside of the plane or using other technology that would give the PLA the upper hand as it develops its own plane.

In the past, just sending a U.S. jet into China would require a presidential waiver. Four years ago, President Obama loosened sanctions the U.S. imposed on China after the 1989 Tiananman massacre to allow “de-militarized” C-130 planes in the region to help in the cleaning up of oil spills. Simply refueling those planes inside China required the White House to give the nod to the operation.

The C-17, a stalwart air platform for the U.S. military, is not considered to be at the forefront of American military technology. But it is nonetheless equipped with sensitive equipment, including technology designed to defend the plane against attack that some believe could be extremely useful to the Chinese.

Typically, air show costs would be considered a public relations event and therefore paid for and approved by public affairs officials. But in this case, Pacific Air Forces will bear the cost of the mission – said to be at least $350,000 -- to the air show and pay for it out of “operations and maintenance” funds, or so-called O&M funding.

Funding it that way, and terming the mission by framing it as relating to humanitarian relief, may allow Pacific Air Forces to justify the event. Unlike fighter, bomber or reconnaissance aircraft, cargo aircraft like the C-17 and Lockheed Martin-made C-130 are considered more than warplanes and are seen as a symbol of American support and compassion since they are often used to deliver humanitarian support after devastating natural disasters.

In May 2008, then-Defense Secretary Robert Gates sent two Air Force C-17s loaded with 200,000 pounds of relief supplies to central China after a devastating earthquake struck the region.

In January 2013, China rolled out the Y-20, a massive four-engine cargo that closely resembles the C-17. However the plane’s jet engines appear much smaller than the massive Pratt & Whitney power plants on the C-17 and experts say it is inferior to the American-made plane.

Even though the U.S. has had little military-to-military cooperation with Russia over the years, the Air Force has looked for partnering opportunities with their Russian counterparts in recent years.

The Air Force took a C-17 to the Moscow International Aviation and Space Salon in 2007. Now, despite what some have termed the beginning of a new Cold War with Russia and the severing of nearly all military-to-military ties, the U.S. and Russia have planes sitting side-by-side on a tarmac inside China.

“We’ve been canceling everything with Russia, and now we’re going to be within spitting distance of them,” said a government official.