A look at how party unity differs between Democrats and Republicans, with a case that the GOP is easier to keep in line.

• Democrats are a "big tent" — conservative, moderate, progressive, and far-left members all under one roof.
• That range means Democrats often disagree internally, even if they close ranks in public.
• Republicans have almost no moderates left in Congress — members are either right or far right.
• With less ideological spread, Republicans have an easier time agreeing when they debate issues.

Outlook: Expect Republicans to stay more disciplined on votes and messaging, while Democrats keep wrestling with their wider internal split.