Howard Dean may not have won a primary or caucus yet, a circumstance that led to a major shake-up of his campaign on Wednesday, but his mark on the party is unmistakable. His defeats are less a victory for the Democratic establishment than a sign of the other leading candidates’ ability to adjust, and harness the energy originally tapped by Dr. Dean’s insurgent campaign: the anger at President Bush, the opposition to the war with Iraq, the demand for a different direction in domestic policy.