1. Money isn't everything. Tom Steyer poured millions into Nevada and came in last.
2. Experiences isn't everything. On paper Joe Biden was the best candidate. A U.S. Senator for over 30 years, and Vice President for 8, he should have been able to make the case he was the most electable. He's been undercut by his personal performance and a crowded field that seems to have made him more desperate and less stable. The result is Biden tied for second place with the former Mayor of South Bend, Indiana.
3. The past comes back to haunt you. Four years ago there was a perception that Bernie Sanders had the nomination stolen from him by party operatives who had chosen Hillary Clinton instead. Her defeat seems to have proven their judgement wrong and now it's Sanders' turn.
4. Momentum is a thing. Sanders has won the first three contests and the perception he is unbeatable. The opposition is divided and unless they were to unite behind a single well funded candidate for Super Tuesday that perception will the reality.