An NBC News poll shows Clinton and Sanders virtually tied at 49% and 47%. That makes the Washington Post story, Leading liberals begin new push to unify Democrats around Clinton, sound a bit desperate. Especially, when you read the article and the only "leading liberal" that they mention as a Clinton supporter is Jerry Brown and the NRDC Action Fund.
They also mention Elizabeth Warren, but she hasn't endorsed Hillary and has only spoken out some more against Trump. Weak stuff if the troops are supposed to be rallying around her.