On May 5th, 1818, Karl Marx, hero of the international proletatiat, was born. His revolution of Socialist theory reverberates throughout the world carries on to this day, in increasing magnitude. Every passing day, he is vindicated. His analysis of Capitalism, development of the theory of Scientific Socialism, and advancements on dialectics to become Dialectical Materialism, have all played a key role in the past century, and have remained ever-more relevant throughout.
He didn't always rock his famous beard, when he was younger he was clean shaven!
Some significant works:
Economic & Philosophic Manuscripts of 1844
The Eighteenth Brumaire of Louis Bonaparte
Critique of the Gotha Programme
Manifesto of the Communist Party (along with Engels)
And, of course, Capital Vol I-III
Interested in Marxism-Leninism, but don't know where to start? Check out my "Read Theory, Darn it!" introductory reading list!
Considering international systems are currently dominated by the US Empire, any agreement, no matter how good it sounds, is going to be passed for the benefit of maintainin that Empire. Considering the people of China love their system despite feeling it has a lot of work to be done, and the people of the US hate its own system, there is a clear difference in effectiveness.
As for Joe Biden's deliberate misquoting of Xi Jinping, you need to realize what Xi actually said. It's no surprise that a genocidal Imperialist like Joe Biden would lie, but to take his lie at face value, rather than Xi's own words on the subject and the people of China who view their system as democratic at higher rates than US citizens, is silly.
Xi was criticizing the Western, liberal conception of democracy, not democracy in general. Biden took that critique of western "democracy" and left it as a critique of democracy itself, despite Xi routinely expressing motive to improve democracy. Read the speech Democracy is not an Ornament by Xi Jinping to see what he means. He is specifically advocating for the Chinese democratic model, which has much higher rates of civilian satisfaction than Western models.