Yes, but such a stance has many unwanted consequences:
1. It will disrupt the balance of power & security of this region.
2. It may kick start an arms race which may result into massive weaponization of the entire region.
3. It will raise doubts & suspicion on China's actual intent behind such massive increase of military capabilities.
4. It may result into many new defence alliances and will increase US presence in this region.
1) The balance of power doesn't include the second biggest economy, we are a non factor in our own yard. Didn't the US call for solving this by law? They got the stand your ground law and we are standing ground.
2) That's already happening, but not really, I don't see anything that wouldn't otherwise have happened. Maybe a few subs here a "warship" there, and a few dozen more F-35s by Japan. That's about it, everything else was pre-planned. But if people really want to start an arms race, well let's do it. We keep pumping out weapons that will match the US and in some cases exceed, the rest bar Japan is getting weapons we stop using in the 80s-90s, or brings a dagger to a tank fight.
3) I'm sure they know what it's about more or less, they don't know whether there will be a full on invasion, but changing of the status quo, this they know. But invasion is unlikely, as Americans proved, it's not a great idea, quick war, achieve victory, destroy their military to make them a non factor, pull out like the Gulf war.
4) No it won't Vietnam will try to court the US, but they won't ally, ASEAN minus Philippines and maybe Singapore, the rest is close to China and won't join anti China, Malaysia and Indo are way too far away and hates Australia and mistrust US about the same. There's tension in ASEAN, and anti China block won't form.
Shinzo Abe is helping to keep Koreans neutral. While America will do what it wants as always.
There's also challenge for the US, pulling out of Africa and middle east seems hard at this moment, Saudi, Iran, Syria, Africa, Eastern Europe all are capturing the attention of the US.
Lastly, due to our power, we will be hated anyways, it's not like the Americans were singing praises on us before, at least now we can defend ourselves.