All I have to do is post the differing responses by the respective governments.
I don't even have to provide analysis - the Chinese reaction says it all.
There was no such statement that the Chinese 5 vessel sail-by constituted "a show of military force intended to militarize".
Identical situations.
The USA said this in early September:
China says this:
Ooh lovely, I was hoping someone would try to make this claim.
Here is why the two cases are different.
The Chinese transit through alaskan waters was indeed part of freedom of navigation as it was the only route in which they could have travelled and they did not linger, whereas the USS Lassen's route was not in line with what could be considered innocent passage.
The Chinese foreign ministry explained it quite clearly in their press conference
Second, last month, Chinese naval vessels sailed within 12 nautical miles off the coastline of Alaska. There was no strong reaction from the US military as they took it as innocent passage. Some people compared China's reaction with that of the US. Do you think they are comparable?
On your second question, the Spokesperson of the Defense Ministry of China has already made a statement. The Strait of Tanaga is for international sailing. In accordance with the UN Convention on the Law of the Sea and the geographic condition of the Strait, all ships passing the Strait have the right of transit passage. What Chinese naval vessels have done is in line with the international law and international practice.
The US naval vessel took the liberty to sail across waters off islands and reefs of China's Nansha Islands. It is completely different from transit passage and is nothing close to the so-called exercise of navigation freedom. Instead, it is a threat to China's sovereignty and security. The Chinese side is firmly opposed to that.
And if you think the Chinese are pulling this out of their hat, there are even those on the US side who have said that the US was deliberately sailing across those waters different to China's innocent passage through Alaskan waters.
The Chinese are cranky about “innocent passage.” They often take offense at any foreign military vessel passing through their territorial waters without prior permission. But in the case of the South China Sea, just asserting the right to sail through may not be enough. That’s because international law, as
most nations interpret it, allows innocent passage even through territorial waters, that 12 nautical mile zone around their shores. So if the US just sails past Chinese-built artificial islets without doing anything else, that’s perfectly compatible with China’s claims that the islets are sovereign territory.
“If US ships … just drive through and demonstrate innocent passage… that doesn’t say whether those islands are real territory or not,” said Clark.
To make a clear statement that the islets are not Chinese territory and the 12 miles around them are not Chinese territorial waters, the US forces have to conduct some kind of non-“innocent” activity.
This doesn’t have to be much, said Bonnie Glaser:
“One option is to loiter in the area of 12 nautical miles for a period of time, not just travel from Point A to Point B, but spend an hour or two, or maybe go around the island.”
More likely, however, is some kind of explicitly military activity. The
says a US destroyer will be shadowed by a P-8 Poseidon surveillance plane. “Having the surveillance [plane] is certainly a military activity in and of itself,” said Glaser. “If it’s accompanied by a P-8, that would check that box. The ship itself wouldn’t have to do anything additional.”
[UPDATE: This seems to be the approach actually taken Tuesday morning]
If a ship were not accompanied by aircraft, it would need to conduct some unmistakably military activity: deploying its towed-array sonar to practice hunting submarines, for example, or launching a helicopter to look around.
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So yes, the fact that the USS Lassen loitered near the waters in what was not innocent passage in the same way that the Chinese transit through Alaskan waters was considered innocent passage. In other words, the USS Lassen was there deliberately in a non-innocent passage context. However the reason China was irritated probably had nothing to do with the fact that it was within 12nmi, but more because of the
intention of why the USN ship was there in the first place, likely in the larger context of Taiping islands EEZ.