Can the Democrats expel this Van Loser guy?

[Hortensis]

27. No, that's his choice, AND HE'S THE CHOICE OF HIS VOTERS.

The constituents in his district are the ones who will decide what they think of this. Now, if he'd molested a child, the caucus would take serious action, and presumably that would not block the wishes of those who elected him.

As for why, note that the liberal-dominated Democratic Party is egalitarian by nature and extremely diverse in makeup. For both reasons, our congressmen don't just take orders from above and are seldom given them, being wooed instead. They have to be free enough to represent their very different districts.

In contrast, the conservative white man's Republican Party is far less egalitarian and more authoritarian and conforming* in nature, hierarchical in structure (power at the top), with diversity in income and education but not much else. Their congressmen expect to take orders from the top, and that can work without completely destroying their ability to represent (resulting in voter rebellion) because of conservatives' general approval of conformity and because of their relative lack of diversity.

* Putting a greater value on conformity is one of the big basic differences between conservatives and liberals. Attitudes toward equality are the biggest difference -- for liberals it's a top principle, with inequality believed to be wrong and a problem to be solved.
Conservatives tend to believe inequality is natural and if not overdone desirable and necessary.

Anyway, all this has big effects on how our representative government works.