[aksss]

In practical terms the US is limited to two parties. Name the last time a third party won the Presidency. This is woven into the structure.

This doesn't limit the spectrum of opinions of individuals by any means but it does compel some degree of consensus and organization to mount a serious campaign.

> They will likely pull the Dem party to the left

Yes, the parties vacillate in how far left or right they are, and the center moves accordingly. Still, the center of US politics isn't defined by some "objective truth" it's defined by the relative position of the two political parties. Some ideas that have been centrist in the past are now extremist, some ideas that have been considered extreme in the past are now considered the accepted consensus.

[tsimionescu]

In the end this is just a matter of definitions. For my own understanding, I define left and right and center in terms of the relative opinions of the population, not the parties. You define them by the parties' positions - that's fair of course, it's a workable definition.

I do think there are advantages to my definition - by your definition, the majority of the US population has an extreme left position on Medicare for all, as an example.