The motivation for building these islands is mostly economic since a crazy amount of the world's merchant trade passes through South China Sea so having control of the shipping lanes holds pretty significant power. China's always felt claims on these waters and this was intended to further reinforce those claims.

Will it lead to military action? They're certainly taking a very strong stance that they are willing to do what it takes to protect what they feel is their rights. Back in August China put out a naval recruiting video that really was more of a political statement to the world in many aspects. In this video there it stated “The struggle over our sea rights is not over. We will not yield even the tiniest speck of our resources.”

China has made a very strong commitment to it's maritime strength now being on track to be the 2nd largest naval presence by 2020 with a goal to eventually surpass.

It's unlikely China will actually invade the mainland of any Southeast Asian country from those islands. Naval operations may occur, but they are likely to be limited to the defense of said islands and the resources contained within. The biggest likelihood of war in my view would be over something such as an oil drilling operation in a contested area.

I think VillageIdiot is on the right track. It's more about force projection and national self-esteem than an overt drive to engage in hostilities.

China has felt inferior to the West for a long time. Now that they are (or have been) an economic powerhouse, they've got the urge to start swinging their dick around.

I've been watching some videos about this topic. Very interesting:
https://youtu.be/WejSKbicS00

It expands the area that China can claim for territory and mineral rights. Most of that area is contested and the US would be forced to support the other countries in that area against China.

That's about it, they're drawing the line in the sand and forcing others to have to 'cross it' and be responsible for initiating the hostilities. As far as China is concerned they now have land terrirory there so they are playing within the rules that have been forced upon them by the rest of world.

Like PE said, pretty much from China's first historical interaction with the west they've had a pretty rough time and really got knocked off their pedestal due to shame of being strong armed, resources taken from them, terms dictated to them, the whole opium thing, yadda-yadda..

So now China's became that bullied kid from high school who spent the next bunch of years going to get his MBA, start-up a gazillion dollar company, got braces and a nose job and cleaned up the acne, got in killer shape, traveled around the world to get interesting, and grew a tonne of self-confidence. Now he's back to find the guy that used to bully him so he can steal away his girlfriend and buy the Radio Shack he's working at just so he can fire him.

"they're drawing the line in the sand"

Over this line, you do not...also, dude, "Chinaman" is not the preferred nomenclature. "Asian-American," please.

I totally had to Google that reference.

I thought the first reference was Star Trek First Contact.

...the second part, I have no idea. Maybe Walking Dead.

The disputed islands belong to China.

According to China. I'm Chinese and I find that claim suspect at best.

According to you, an illegal immigrant is a citizen.

Gobbledydook: do you mean that you are ethnically Chinese or a citizen of the PRC?

Thanks, Obama.

Both.

As per the UN laws of the sea, China cannot claim as its own territory islands it has artificially built (or so j think) for the purposes of establishing claims on surrounding seas. I actually applaud China doing this, because now it becomes very hard for them to launch any objections at the US or any of their neighbors without doing some serious doublespeak. India and the rest are not being fooled.

The fastest growing navies behind China? I believe they are India and Japan. Let's not kid ourselves - we're in a naval arms race with China right now. It doesn't take a long look back through history to see how those end up. (Spoilers - the fast rising number 2 always gets put in its place by number 1)

@Gobbledydook: Interesting, I wouldn't have guessed. Mainland or Hong Kong?

Based on your English, I'm guessing some form of Hong Kong/rich parents/or time spent studying abroad?

Hong Kong.

For what it is worth China knows it cannot claim the reclaimed islands through maritime laws. The aim of the reclamation work is to force the issue de facto.

There are however natural islands in the South China Sea and I think China has at least some claim to those.

When you're talking about China's navy, it is important to remember they are a regional power only (militarily speaking). You're talking about one air craft carrier, no cruisers, a handful of destroyers. They do have a lot of frigates. They challenge all of their neighbors, but they lack the ability of force projection. Their real threat is in subs. Compare that to the US. Nearly a dozen air craft carriers, 20 cruisers, 60 destroyers. Not to mention the technological advances that we have. I really hope that Congress approves more Zumwalt class destroyers, cause those things are badass. With the new direct energy weapons, and the rail gun going on the third one, not to mention the stealth design and increased automation, these are the ships of the 21st century.

Are they actually putting rail guns on combat ready warships?

The Lyndon B Johnson will have a railgun. It will be the first ship to carry one. The USS Ponce, an LSD, already has the direct energy weapon (lay man's term, laser gun) that they are planning on putting on the Zumwalts as well.

I also believe they are trying to make the systems modular so that it would be relatively easy to install railguns on the first two if it works well on the third.

So basically Advanced Warfare is coming to life?

In the U.S. military, yes.

Great. Remind me why we still put soldiers' lives on the line then?

Because not all situations calling for military involvement are readily resolved by shooting railguns from warships? (I do think the US has frequently been guilty of calling for military involvement unnecessarily, though.)

Yes, the U.S. is overzealous in some things. It just happens that those things happen to be the large scale stuff like Iraq or Afghanistan. But what you don't see is the small scale stuff. Heck, just in the past week the new USS Zumwalt was undergoing sea trials and rescued a couple of fishermen.

Other countries disputing the islands have already illegally occupied the natural islands. Therefore, China has no choice except to build artificial ones.