Foreign policy has shifted from international co-operation
With US dominance fading, and countries jostling to be the next hegemon, foreign policy is increasingly self-interested. Just look at Brexit - cooperation is fast moving to being a thing of the past.
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The attempt to purchase the rights to the COVID-19 vaccine is representative of a bigger paradigm shift. That is to say, the downfall of multilateralism.  The crisis of multilateralism can be attributed to multiple factors: disillusionment with globalization, poor narratives depicting support for global cooperation, and the inadequacy of existing rules to meet new challenges.  As the countries of the world remain tightly linked at the present moment, shocks to central players like the U.S. or China can often prove paralyzing; the very reliance on centers of power generates systemic risk. This idea is specifically witnessed in the 2008 recession as well as how the COVID-19 outbreak that began in China and the way in which it quickly became a global health and economic crisis. Thus, the pandemic may assist the decline in a cooperative global landscape. This is specifically due in part to world leaders' inclination towards populist ideals and their fervent fanning of nationalist sentiment, framing the rights and interests of their own nation as being pitted against that of the global community. 
International leaders are not shifting away from a co-operation based system, rather these countries still have every intention of cooperating with one another, they are simply finding a new balance in a reality without the looming power of the United States. This is especially true in light of the COVID-19 pandemic. That is to say, global risks demand more multilateralism, not less. Whether it's the risk of North Korea developing a functional nuclear weapon or a highly contagious disease, the present is marked by increasing uncertainty. Yet, all of these issues are international; they are not bound by national borders. Thus, international powers are looking to increase global co-operation as a method of solving such problems. Yet, as America takes on a more individualistic attitude this once perfect balance is thrown out of harmony, giving an illusion of decreasing multilateralism. In reality, this is not the case as made clear by the persistence of co-operation on issues pertaining to political conflict, climate change, environmental degradation, and as mentioned previously the pandemic. 
Rejecting the premises