Well China does view Taiwan as part of it but that doesn’t mean they would go to war at the drop of the hat. I think they would consider the possible repercussions and are only likely to attack if the situation changes. I also think the connection between our Taiwan policy and Japan and Korea is overstated we have actual troops on the ground in both Japan and Korea which makes a major difference in determine our reliability in a fight. I think it might also be worth noting that our stated policy on Taiwan over the years has changed and incorporated various degrees of ambiguity with no obvious ill effect on our relationships with outer states.