A third world war in the foreseable future is highly implausible

NATO is the most successful Alliance in the history of the world and it is successful because of its shared values and the commitment to collective security. That is an unshakable guarantee and I am very confident that the members of the Alliance are safe. The fact that the Alliance continuously looks at its’ structures, procedures and policies and the fact that NATO works very hard to be effective, and its’ historical success is what will guarantee that it is still here ten years from now. As the principal and most effective security framework in the world. [h2]

Mutual assured destruction, principle of deterrence founded on the notion that a nuclear attack by one superpower would be met with an overwhelming nuclear counterattack such that both the attacker and the defender would be annihilated. ...Commencing with U.S. Pres. John F. Kennedy’s administration, greater emphasis was placed on a doctrine of all-purpose flexibility, including a larger conventional ground force as well as counterinsurgency forces to deal with “brushfire wars” such as the one in Vietnam. [britannica]

The ongoing dispute over Taiwan, for example, is ripe for troublesome misperception.....Despite all of the above, we believe that the recent clamor over China’s strategic ambitions is greatly overblown. Most of the Chinese aims that run counter to U.S. interests are in fact not global or ideological but territorial in nature, and confined primarily to the islands and waterways to China’s south and southeast. In addition, Beijing has recently taken a number of steps to cooperate with the United States on security matters: signing the Chemical Weapons Convention and nuclear test ban treaty, terminating its assistance to nuclear facilities in Pakistan, pledging to cut off ballistic missile transfers to Pakistan as well as nuclear and anti-ship cruise missile trade with Iran, and quietly restraining the North Koreans. Moreover, China is plagued by enormous socioeconomic problems, whose solution requires maintaining good relations with the world’s major economic powers—and with the United States in particular. [3]

China will not represent a serious strategic threat to the United States for at least twenty years. [6]

There is no sense of an imminent threat - or that Russia's President Vladimir Putin has decided on invasion. But he has spoken of "appropriate retaliatory military-technical measures" if what he calls the West's aggressive approach continues.

US military support for Kyiv, in Mr Putin's eyes, is taking place "at the doorstep of our house". Russia is already concerned by Ukraine's deployment of Turkish drones against Russian-backed forces in eastern Ukraine and Western military exercises in the Black Sea.

Russian Deputy Foreign Minister Sergei Ryabkov has warned that tensions could lead to a situation similar to the 1962 Cuban missile crisis, when the US and Soviet Union came close to nuclear conflict.

Russia also accuses Nato countries of "pumping" Ukraine with weapons. Accusing the US of stoking tensions, Mr Putin said Russia had "nowhere further to retreat to - do they think we'll just sit idly by?" [8]

Putin has maintained power for two decades by standing up to the West without taking big chances. Invading a nation of 40 million where four out of five inhabitants are non-Russian would entail incalculable uncertainties—uncertainties that might ultimately endanger Putin’s hold on power. Taking such risks would be out of character. [ibid]as

• China soon invading Taiwan isn't proven by PRO; and certainly doesn't automatically imply a world war
  
• Russia had no intentions of conquering Ukraine, so there is no potential for a world war starting there
  
• China and Russia cannot realistically win a conventional war against NATO
  
• An alliance between them to fight NATO is a preposterous claim without evidence
  
• The near certainty of defeat/stallemate/tie makes such an alliance and war absurd on its face
  
• No motivation to attack the EU or the US has been presented that would make sense of such an alliance
  
• The geographical landskape prevents effective military cooperation during war
  
• Neither China nor Russia can help each other directly by joining the other's war
  
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• The risk and cost associated with major wars far outweight the potential benefits, territorial gains included
  
• The two superpowers planning a world war with Nato is an absurd notion, as they have no incentive or realistic capacity to do so
  

• No colonial or imperial nation exists today, and superpowers are not in close proximity to each other. Regional wars will stay regional, preventing a world war.
  
• Democracy ensures peace in former war-ridden areas like Europe. The rising number of peacefull democratic nations constantly reduce the risk of war.
  
• Alliance blocks today are not balanced as to make the outcome of war uncertain. NATO is powerful enough to discourage and prevent major wars.
  
• Nuclear weapons have already prevented a world war in the most polarized, tense and hostile world in history. MAD makes war undesireable for everyone.
  
• Economy and trade is far more vital to a modern nation than winning territory or other gains in war. Preserving the economy necesitates staying at peace.
  
• Superpowers are far better off increasing their diplomatic influense peacefully than ruin their international status by starting an aggressive war.
  
• The geograhpy of the world is such that the superpowers are separated by oceans and continents, reinforcing the fact that war is not worth the effort.