What if China attacked Taiwan ... and lost?

It seems to me that there is a tendency to automatically assume that China, because of its larger resources, would win, if it attacked Taiwan. However, as the Caspian Report  recently pointed out, invading Taiwan is militarily challenging. (A recent analysis by the Strategy Stuff channel looked at historical invasions, but those were times when populations were low, and technology simple: I have doubts that those successes and partial - even back then - successes can be applied to modern military situations.) The outcome would partially depend on relative air strengths over Taiwan, and I'm surprised that technologically savvy Taiwan hasn't developed something like remotely piloted, unarmed, lighter & cheaper but supersonic drones to check China's many air incursion threats to reduce wear and tear on their aircraft and pilots (of course, it could be that we just don't know about that, or it is underway). 

The outcome would also depend on how well Taiwan could protect the strait between it an the mainland, and I don't know that they have enough resources (only two submarines) to attack an invasion fleet, meaning resistance on the beachhead will be crucial - which is where the air force becomes significant. 

Again, I'm not in on any loops of info there (and don't want to be), so there may well be more to this than I know - and military proficiency of the US backed forces vs. China's recently modernised (I don't consider too many lessons can be drawn from what happened in the Korean War) forces will also be an issue.

It all comes down to there being a possibility that an invasion by China of Taiwan could also possibly result in: 

• China losing decisively (the decisive outcome of the Six Day War was not expected by many or any?] ); or 
• a prolonged stalemate - a little like either a modern version of World War One's Western Front, or perhaps guerilla tactics as China used during the Japanese invasion of the 1930s and 40s (a strategy recommended by a US officer [ironically, the two best Chinese divisions were trained and equipped by nazi Germany in the early stages of that conflict) or Việt Nám used against the USA in the 1960s and 70s. 

Those who discount those possibilities may be making the same errors of hubris-arrogance that so many made during the July Crisis before World War One - and, at that time, many knew that the crisis could lead to a world war.

So, in brief, if there is a decisive and relatively quick loss: 

• Xi would be weakened, and even more hard-line militaristic forces could gain more power - and resentment at the blow to China's importance (which includes a desire for acknowledgement of that by other nations - which was a major driver for Germany and Austria before WW1) would linger; 
• Taiwan runs the risk of complacency; and 
• a further conflict would be almost inevitable unless the loss is so severe that China chooses to allow Taiwan independence (I don't consider that at all likely), and a future invasion would be even more likely than one is now - and I suspect that would lead to a victory for mainland China.

PS - Another risk is China may seek to save face by attacking elsewhere. 

If a stalemate develops: 

• resupply of munitions and other logistical issues would become critical, and that is where Taiwan's US backing (see here, here, and here - and the openness of that support, which was lacking in July 1914, is of some significance) would become critical, along with whether the USA is prepared to risk war with China; 
• the longer the stalemate continued, the greater the risk of another world war - possibly nuclear. 
  

China is determined that Taiwan will be reintegrated by 2050 (see here, here, and here) - and there'll be none of the duplicity of the "one nation, two systems" lies that led to the British abandoning Hong Kong to its current fate. 

This situation is a very significant threat to world peace and, given the risk of any broader conflict (which would include Russian backing, unless there is a significant change there towards democracy after Putin) being nuclear, a possible threat to human existence.

It's time for diplomacy that goes beyond self interest.