Jennifer Rubin summarizes  Marco Rubio’s fear-mongering about possible Chinese hegemony:
He tells us we can’t check out of the world but must engage economically and not leave world leadership to countries like dictatorial Communist China [bold mine-DL].
This is an argument that hegemonists have been falling back on more and more often in the last few years. It’s a very weak argument for maintaining the foreign policy status quo, and it’s an entirely negative case for what hegemonists call U.S. “leadership.” In short, the argument is that if the U.S. doesn’t continue to have a hyperactive foreign policy and meddle in countries all over the world (i.e., if it doesn’t “lead”), the world will fall under the sway of China (or Russia).
It’s a nonsensical argument for several reasons. First, Russia and China have neither the means nor the inclination to take the place of the U.S. as the world’s preeminent power. Second, the other major powers in the world would not be willing to tolerate global “leadership” from China or Russia. China’s ambitions in the South China Sea have managed to generate significant resistance from almost all of its neighbors, so one can only imagine how resistant they would be to even grander Chinese schemes for global “leadership.” It’s preposterous to worry about China replacing the U.S. in its current “leadership” role, and the fact that this is what Rubio is reduced to arguing suggests that the positive case for that role is also exceptionally weak.