China would like to push America out of the western Pacific. That would allow China a free hand to attempt to dominate neighbors who would no longer have American help to resist China.
But any serious attempt to defeat apparent targets like Japan, Taiwan, or the Philippines risks war with America. Contrary to imagery, we are far more powerful than China. Unless we give up after enduring the first blows, we can muster a lot of force to smash up Chinese naval and air power.
But China could raise their stature much as Japan did more than a century ago--smash up the Russians.
Russian military power is thin in the Far East. Russia has few people there, too. So Russia is vulnerable there to Chinese power.
Sure, Russia has lots of nukes. But they are useful only for national survival issues. If Russia uses them in something less dire than that situation, Russia may guarantee nation failure by prompting Chinese use of nukes in return.
And China and Russia (when they were Soviets) did slug it out on a small scale before without it going to nuclear war.
Remember, too, that despite images of Russian-Chinese friendship, Russia is scared of China, with Russian policy really a form of appeasement while Russia desperately tries to reverse the power imbalance; and China has dormant territorial grievances of relatively recent origin that could easily be revived as China's absolute and relative power increases.
So the forces pushing China and Russia apart are stronger than the forces pulling them together in the short run:
The idea that Beijing might march on Vladivostok is obviously far fetched, but it is not terribly hard imagine well-placed hawks musing about the legitimacy of Russia’s borders if the two powers should find themselves at odds, just as Mao and Zhou did in the 1960s. (In a more recent example of such irredentist escalation, scholars at a state-backed Chinese think tank questioned Japan’s claim to Okinawa.) Indeed, far beyond Manchuria, possible sparks already abound: from Central Asia, where booming trade with China threatens to erode Moscow’s traditional sphere of influence, to the South China Sea, where Russia has worked closely with Vietnam to develop and safeguard energy resources claimed by Beijing. “In the parts of the world that matter to them most,” Jeffrey Mankoff has noted, “Russia and China are more rivals than allies.”
It would be very risky for China to march on Vladivostok. There is the risk of nuclear war, even if logic says the risk is remote for such a limited loss to Russia.
There is also the risk that China's impressive looking military is still weakened by historic forces of corruption. Failure in a major land conflict with Russia would undermine China's power as much as victory would increase it.
Could China hit Russia's fleet and air bases in the Far East and combine that with a quick, overwhelming hit on some Russian border post that provides the image of land dominance, too?
Sure, Russia may very well have sold naval and air weapons to China in order to point China's power at America.
But given China's recent navy trip all around Japan following joint exercises with Russia in Russian waters, that air-naval power could just as easily reach the Russians now.
Given how Russia promotes anti-American propaganda and given how Russia is still at war (technically) with Japan on the issue of Russian conquest of Japanese territory near the end of World War II, who would step in to help Russia?
If the Chinese could actually inflict a quick defeat on Russia, ended the fighting before it could escalate, could they use the leverage of that victory to get the Russians to make a small adjustment on the common border that would at least set the precedent for more later (to undo that 1858 unequal treaty)? Or what if there was no territory change, but the Chinese get the Russians to concede Chinese economic interests in the Far East as a step back to establishing claims to the land much the way Russia eased their way into the territory?
And perhaps the Chinese could demand that Russia end their arms sales to Vietnam.
An outcome like that would set Russia back, isolate Vietnam (forcing us to make a choice there to abandon Vietnam to China or increase support), and cause other nations in China's shadow to wonder if they are safe (new Domino Theory, anyone?).
When we think of China's rising power, we naturally think of how it might be directed at us. But from China's point of view, there are safer targets than America. So if we think about whether China might use their growing military power, don't fixate on America and our allies.