UPDATED: Adds House Letter To White House CAPITOL HILL: Defense officials acknowledged today that the US has not directly challenged the sovereignty of China’s artificial islands in the South China Sea for at least three years. US aircraft have not flown over the artificial islets. Nor have US ships sailed within 12 nautical miles of one since 2012 — when most of the current crop weren’t even built.

Those facts raise the question of whether Defense Secretary Ash Carter’s pledge earlier this month was a hollow one. “The United States will fly, sail, and operate wherever international law allows,” even in Chinese-claimed waters, Carter said Sept. 1st. These declarations are particularly pointed, and the discussion relevant, because Chinese President Xi Jinping is visiting Washington at the end of this month.

The 12-mile limit in particular is a big deal, because it’s the extent of the territorial waters the Chinese claim to control around their new constructed “islands.” The US argues an artificial “feature” built over a submerged coral reef grants no legal rights to the surrounding waters or airspace. (China in fact claims almost the entire South China Sea, based on an infamous “9-dash line” on a World War II-era map, which US and Asian nations naturally reject.)

This morning’s exchange between Sen. John McCain, who has bipartisan support for his view that China must not be allowed to build and operate these structures without being challenged, was dramatic.

“We sail and we fly and we operate within that area on a daily basis,” said David Shear, assistant secretary of defense for Asia-Pacific security, including “freedom of navigation” operations to assert our rights to free passage as recently as April.

“But you haven’t operated within 12 miles of these reclaimed features, have you?” asked McCain.

“We have conducted freedom of navigation operations….” Shear began.

“Have you gone within 12 miles of a reclaimed area?” McCain interrupted.

“We have not recently gone within 12 miles of a reclaimed area,” Shear acknowledged.

So when was the last time? McCain demanded.

After some pushing and prodding, Shear said that “I believe the last time we conducted a freedom of navigation operation within 12 nautical miles of one of those feature was 2012.”

“2012,” McCain said grimly. “Three years ago.”

Under questioning from McCain’s Democratic counterpart, SASC ranking member Jack Reed, Adm. Harris added that “we have not conducted a flyover” over Chinese-reclaimed land masses, either.

Even as purely physical structures, the artificial islets are affecting the balance of power. China is building deep-draft harbors suitable for warships and three 10,000-foot runways that can handle any aircraft short of the Space Shuttle, the chief of US Pacific Command, Adm. Harry Harris, told the Senate Armed Services Committee.

If the US refuses to challenge the islets’ legal status by sailing or flying within 12 miles, they effectively become bubbles of Chinese sovereign territory in disputed and strategic waters. “If you respect the 12-mile limit, then that’s de facto sovereignty, agreed to tacitly,” the Senate Armed Services Committee chairman, John McCain, argued at today’s hearing.

[Update begins] Just a few hours later, 29 members of the House — a bipartisan group led by hardcharging Obama critic Randy Forbes, chairman of the seapower subcommittee — issued a letter to the administration that echoes McCain’s arguments and urges operations within the 12-mile limit.

“Continued failure to actually exercise that right [to go within 12 miles] could be interpreted as de facto acceptance of Beijing’s destabilizing behavior,” the legislators wrote. “We believe that a firm response from the U.S. government, including the highly symbolic passage of American ships and aircraft through the waters and airspace illegitimately claimed by China, is needed to reinforce and sustain the international community’s opposition to extralegal claims.” [Update ends]

If the US does come within 12 nautical miles, however, the prickly Chinese are likely to see it as a challenge. What’s more, 176 years of national trauma dating back to the Opium Wars mean Chinese commanders can react dangerously, even violently, to perceived threats to national sovereignty. (This is the Chinese perspective on why they entered the Korean War). The US has tried to keep good professional ties with the Chinese military to help manage tensions, but even so, it seems clear US policymakers are not sure how to press the issue of the islets without risking serious escalation.

Challenging these sites may require carefully managed but dangerous collisions — and even deaths. Different sources tell us contradictory things about whether or not Pacific Command has ordered its pilots and ship captains to stay 12 nautical miles away from the islets as a precaution.

Shear hastened to say that sailing and flying through a Chinese-claimed area is just one option out of many, and that it is an option on the table. “Freedom of navigation operations are one tool in a larger toolbox that we’re going to need to use,” he said. “As we move forward, we’re going to consider freedom of navigation operations, along with a variety of other options.” He didn’t say what those options are, however.

“PACOM presents options, military options, to the secretary and those options cover the full range,” added Adm. Harris. “We’re ready to execute those options when directed.”

Okay, but which option do you think we should take, asked Sen. Dan Sullivan. “In your professional opinion, Adm. Harris, should we sail or fly inside the 12-mile area?”

Any policy decision has to come from the defense secretary (and ultimately the president), Harris said, but personally, “I believe that we should be allowed to exercise freedom of navigation, [both] maritime and flight, in the South China Sea, against those ‘islands’ that are not islands.”

“In the 12-mile limit?” Sullivan asked.

“Depending on the feature,” Harris replied. “If….”

“What about that one?” Sullivan interrupted, pointing to a photo of the Chinese airstrip under construction on Fiery Cross Reef.

“That one, yes,” Harris said.

The “features” do pose a military threat, the admiral said — up to a point. If the Chinese continue their construction projects, “you can imagine a network of missile sites, runways for their 5th generation fighters, and surveillance sites,” Harris told the senators. “China would have de facto control over the South China Sea in any scenario short of war.”

But in a shooting war with the US, he said, “these are obviously easy targets.”

“China fields a very modern military and a growing capability and capacity, [but] we have a technological edge over them in almost every way, if not in every way,” Harris said. “I’m confident of our ability to take the fight to China if it should come to that. I certainly hope it doesn’t.”

“That said, we have to maintain that technology edge because they are growing,” Harris continued. That particularly means both fielding so-called 5th generation fighters — agile stealth fighters like the F-22 and F-35 — and upgrading existing 4th generation aircraft — the F-15, F-16, and F-18 — because we’ll have a lot of them for a long time.

“We will always have a qualitative advantage,” said Harris. “We have better trained people, better equipment — [but] quantity has a quality all its own.”

As the Chinese forces get both more modern and more numerous, “I worry about the pace of the Chinese buildup against the likelihood or the possibility that we will continue to be sequestered,” Harris said, referring to the Budget Control Act caps on spending. “That will pose a very real problem for us in the 2020s.”