The main problem today with Asia is it has religions that are less tolerating of each other than Catholic, Christians and Judaism.
With the People Republic of China (Communist) regime in place, they are currently trying to wipe out the Tibetans. How do you think Muslims would fair under the PRC?
I would say that before there is a coalition, there will be a great religious war. Whether Islam, Buddhism, Hinduism, Taoism just to name a few, most of the religions in Asia come out of India.
Once the region does form a coalition, Russia is their wildcard. Russia is both in Europe and Asia. Today, Russia is mostly European, but in the future, they could swing over to the Asian coalition.
Russia would be the factor that makes an Asian coalition either weak by its absence or strong by its presence. It also by 2046 could split itself into two countries, one a European and the other an Asian.
Whether or not it can curb NATO power (unless something happens before 2046, US is part of NATO) depends on many factors. While the size of the Army is one consideration, history of WWII taught us that the side with better technology acts as a force multiplier. I spent 3 years in the US Army, and I can say that I would kill more with an M-16 than the M1. The M-16 is a greater force multiplier than the M1.
WWII saw that when the Germans and Italians with their bolt action Mausers didn't stand a chance with the semi-auto of the M1 Garand, the M-14 and the Thompson Machine gun. However, when Germany improved its machine guns, they started to even out the differences between the force multipliers.
If we base the scenario on how population and technology and standing army sizes, just between China and the US, the US is more technically advanced, and it has 81 percent more personnel in the armed services than China does.
Russia, while it does have 41 percent more military personnel that the United States, it suffers the same technology fate that China does. Neither have enough aircraft or ships or tanks to outmatch the US, and that isn't adding in what the NATO countries have.
This is why Russia is a wildcard. If it joins in with the Asian Coalition, then the differences become smaller as far as number of troops, and the gaps in the differences in assets also close a bit.
While I have heard on TV that less people died in the last 100 years than in any other 100 year period going back thousands of years, even by today's most recent number (check the same link will give you the rank of the number of war-time deaths) The NATO coalition with the US will still defeat the Asian Coalition, even with Russia joining them.
As someone versed in military strategy, a coalition set up only for defense will find itself outmatched by an adversary with a good attack strategy. The problem with just defense is once key installations are taken out, you have no chance to organize an offensive quickly enough to do anything. Once your military is deaf, dumb and blind, where will you attack? How can you effectively organize your troops? And if you are blind, you'll never see the next attack coming.
In your story, the Asian Political and Economic Coalition needs to advance their defensive technology to exceed that of the US/NATO's offensive capabilities.
One thing is for sure, this will be one story I can't wait to read.
Even with the information provided, the choice of the battleground can negate technology as much as it can enhance it. As the Russian's could not win in Afghanistan due to its technology was no match for the battlefield conditions, it was only the improvements 30 some odd years later that the US had the ability to successfully fight in the same battlefield conditions. Yet it still had great difficulties in fighting, and as of yet has not become victorious.
They got much closer than Russia ever did.
Good Luck, and I am sure others here will add what I missed.
EDIT FOR NUCLEAR ISSUES:
Now if this is a nuclear showdown that some think will make the difference, a China/Russia Asia coalition loses. Even 20 years from now.
Estimated for 2017:
NATO/US Allies - 7,395
Asia - 7,520
North Korea: 10
Problem is that Pakistan and India will save many of theirs as they hate each other so bad that they will not let China use them all.
Plus, many of the totals above are in the process of being disarmed.
North Korea’s program today is a joke, and unlikely to change as their leader in inept. And while it is claimed that North Korea can reach the US, that missile will never reach us.
The United States has the best missile defense system in the world. And Russia’s best weapon is fired from a truck.
Russia’s nuclear arsenal isn’t as good as it states, according to Jeffrey Lewis of the Arms Control Wonk. Yes, while Russia has a missile that when it enters our atmosphere can fire off 10 warheads at 5 miles per second, they shoot them from trucks. And we have the capability to shoot the missile down while it still is over Russia, which is not a good thing for the Russian people.
Also, Russia’s nuclear weapons program is short-sighted. They invest less money in it, because they believe that they will only have to build newer systems every 10 years. Many of their arsenal dates back to just after WWII.
While China’s nuclear program is growing, we also have the capability of shooting down all their missiles as the map below shows. China is building islands in the South China Sea for the sole purposes of putting nuclear missiles on them so they can reach the United States.
Yet, the US has a secret weapon that no one else has. A autonomous submarine. Yes, launched April of 2016 The Sea Hunt is designed to hunt down submarines, without risking a single crew member’s life.
On the NATO side, by 2030, the Germans will have a tank that will make the Russian T14 obsolete.
By the time 2046 rolls around, Pakistan will still be at war with India. India has started to engage in talks with the United States after China and Pakistan conducted war games in 2016.
We will see a very different Asia by 2046. And while the smaller countries, like Japan, Taiwan, Vietnam, Cambodia, the Philippines will sit out this war, The United States has more airplanes, aircraft carriers, and naval ships to once again own the Pacific.
Since Russia nor the United States will fire the first shot, China will at the United States. Russia has no plans to fight against the United States, but while the US amasses in the Pacific and Asia, Russia will use the opportunity to try and take the Baltic. However, NATO is strong enough now to repel any Russian attack, and if Russia succeeds, it will pay a high price for it.
And that price means that when Asia calls to Russia for support, it will be unable to do so.
We can run scenarios like this for the next 20 years, but due to religious hatred, terrorism, half of the Asian countries do not trust China, China’s first strike might encourage them, but it will also galvanize the world against them, which they will be unable to win.