Can the Far Left Co-exist with Moderate Democrats?

I think "moderate" democrats push the far left off to the green party and other sideshows. The democratic party can either try to include the far left and the left, or the left and moderates, but not all three. This problem is the issue that is keeping the democrats in the minority.

I think the main difference between parties is that the republicans coopted the one or two issues (like abortion and gay marriage) that the far right cares about into its platform, while the republican moderates recognize that nothing can really be done about those issues (because it would require amendments), so they ignore that part of the show. The far left and moderate democrats, on the other hand, differ on policy issues that can be changed, such as whether we go to war, taxation, etc.

If I was part of the far left, I would group moderate democrats with republicans, because they agree with each other and differ with the far left on primary issues. I would feel that the democratic party was not the party that would represent my issues. It makes perfect sense that if the support I give a party will not make my political wishes happen, I won't give that party support. The Far left is in that position with democrats.