If one were to gather political parties from around the world and sort them as left-leaning, center, or right-leaning, one could do so. However when it came time to compare the left-leaning parties of other developed nations with the left-leaning parties of the united states, it would quickly become apparent that the "most-left" party in the united states aligns with center-right and far-right parties of other developed nations. So, doing such analysis you quickly come to realize that the united states has no true left-wing party. We have conservative and conservative-light. It should also be noted that the conservative party in the united states is much further right than most other developed nations.

Also, remember, right-left is a duopoly, much like Pepsi and Coke. There are so many more dimensions to politics than right-left, there's a thousand different parties for every ideology. For more info on this, check out the podcast linked at the end. Support ranked choice voting if you want to take steps to end this duopoly. What do you have to lose? Entrenched life-long, un-removeable politicians. What do you have to gain? Choice. Variety. More direct democratic representation and politicians that better reflect their voter's interests.

Freakanomics
Episode 356
America’s Hidden Duopoly
https://freakonomics.com/podcast/americas-hidden-duopoly-2/