In its early days, Congress wrote a series of rules and precedents — Thomas Jefferson penned a book about it — that Congress has used ever since.

But there are also unwritten rules — and it’s these unwritten rules that break down when politics get excessively polarized.

Some are about helping people get along and ease tension: deferring to elders; not campaigning against other senators; speaking to each other with flowery forms of address.

Here, we take a peek at some of these traditions — and where they fit into today’s Congress.