>>515437414
Due to their economic growth.
Separate from that, Obama tried a "pivot to Asia" and failed. The left is currently obsessed with Russia as well so there isn't much of a chance they would become opposed to China.
It's penny wise and pound foolish in the best case scenario.
Even if the left had a total victory, the trends of modernity (increasing impoverishment for the west and polarization) would not go away. It would be a moment of quiet before another conflagration.
In the long-run, the right is more likely to oppose China.