It's a two party system. If you want to get into a position where you can enact change, you pretty have much have to be subordinate to one party or another.

That us how the fairy tale goes, yes. The more accurate way to describe it is that if you want to join the political class as a member of one if the two major parties (which makes it easier to do so), you must not cross their red lines and you must fall in line.

There is more that could be said about that, but Bernie was elected as an independent and has a safe seat. As such, he could provide a vision and build a movement if he wanted to. Instead, he supports genocide. There is no strategem. It is just an old liberal supporting the system he has supported since the 80s.

If your party is guaranteed a landslide victory (or hell, guaranteed no victory), then by all means feel free to state your true beliefs in a bid to drag them back to the left.

This is the same false logic I addressed in my previous comment.

But this is going to be a close call election. Better to sleep with a tired donkey who might let you have a voice later, than a deaf elephant who will let you have no voice at all.

The opposite is actually the case. It was far easier to advocate left ideas under Trump than under Biden. Liberals go to sleep between elections when their party is at the helm. They become the defenders of the status quo rather than "the resistance" (lol).

The things you are saying are lines handed down by PR strategists hired by the party over decades. They are not true, just common and often repeated. Their purpse is just to keep you a reliable voter despite them not delivering for you.

If you are elected into a position where you can enact change, those who elected you have expectations of you based on the policy you supported during the election.

If, then, you turn around and do something completely different your actions no longer reflect the will of those who elected you, and you are not behaving in a representative manner and thus in an undemocratic way.

So ignoring anything specific to the American system, class interests, etc., it is a losing battle to try and be anything different from the status quo and getting elected by aligning yourself with the status quo.

A communist who gets elected by siding with a fascist is no longer a communist. A liberal cannot be a liberal if they denounce capitalism and side with socialists. They are fundamentally different ideas of who the political economy is designed for, completely contradictory ideas about hierarchy, property rights, human rights, and even what constitutes truth (liberal ideas are often utopian, like the "rational economic man", and socialist/communist ideas are often based in the reality of the current and past material conditions, like believing people need homes and food, and a wealthy society should be able to provide these for itself, so people get homes and food. In contrast a liberal society would let the "market" provide these things in whatever way is profitable.