Chinese Foreign Minister Wang Yi saved his stoutest defence of Beijing's deployment of military hardware in the South China Sea for his last day in the United States, explaining in detail why his government considered it both necessary and legitimate.
Over the course of his three-day visit to the US, China's top diplomat had provided snippets of his government's rationale for its activities in the region, but before an audience at a Washington think-tank on Thursday, he put it all together.
His argument was built on three broad points: The situation in the South China Sea was not as bad as it was made out to be, Beijing is merely playing catch-up with other parties in the waters and expansionism is not in the Chinese DNA.
At the same time, he accused the Philippines of violating agreements between the two sides by bringing a case to the United Nations tribunal, and voiced concern about US talks with South Korea about deploying a missile defence system in the Korean peninsula.
In particular, Mr Wang said the X-band radar associated with the Thaad (Terminal High Altitude Area Defence) impinges on Chinese national interests.
"The X-band radar... has a radius that goes far beyond the Korean peninsula and reaches into the interior of China. In other words, China's legitimate national security interests may be threatened," he said at the Centre for Strategic and International Studies (CSIS). "A convincing explanation must be provided to China. I don't think it is too much to ask. It is a reasonable position."
When the moderator, CSIS senior adviser Chris Johnson, subsequently asked if Beijing's opposition to Thaad contradicted its own assertions that it had a right to deploy military hardware, Mr Wang stressed that its deployments were critical for defending itself in an already heavily militarised area.
"It is true that we have some defence facilities on islands and reefs, but what you should see is that the islands surrounding China and the reefs surrounding China have more military facilities on them," he said.
"There are various kinds of guns, amphibious tanks, airstrips, runways, planes.
"There are missiles and for China's islands and reefs (facing) towards so many military facilities, we certainly need defence facilities. This is a right of self-defence bestowed by international law."
Still, he noted that the situation was stable and that no commercial ship has complained about a lack of freedom of navigation in the region. In a thinly veiled call for the US not to interfere, he added that China and Asean were capable "on its own".
In fact, he said that China's ultimate intention was to build public goods on the island like lighthouses, meteorological stations and emergency harbours.
Tension has been growing on the South China Sea issue since reports this month that Beijing had deployed surface-to-air missiles to a disputed island and is building a military radar system on another.
During the event, the Chinese Foreign Minister also sought to downplay the apparent growing competition between the US and China, stressing that the two are interdependent. And he stated categorically that China does not want to replace the US.
He said: "Some friends in the US are worried. They view China as the major adversary of the US, and one day China will replace the US. Such an argument has behind it a strategic mistrust, a strategic suspicion in the long term. And if such a mutual mistrust develops, then it will make us concerned because smaller problems will grow into bigger ones."
But even here, Mr Wang left some choice words for the US.
"Do we think we will replace the US? We are not the US. China is China... In the blood and the veins of China, there are no veins of expansionism, there is no mentality or urge to be saviours of the world," he said.
"Starting 2,000 years ago, we built the Great Wall of China for self-defence. That is the special characteristic and the very typical expression of the features of the Chinese culture. Such features ingrained in the genes of China will continue."