I was at the march in NYC. It was cordial and respectful. Some of the signs were a bit close to the cuff, but there was no trouble, and people sang with heart the national anthem before the main rally began, and applauded the passing fire trucks and police cars.
As far as what's at stake:
Abortion limitations.
LGBT rights.
Public education as we know it, with alternative proposals ranging from vouchers to online learning.
And on and on and on...
The marchers were a diverse bunch. They were tony, working-class, smartly dressed, not giving a damn about how they dressed, white, black, Hispanic, day, straight, from a few months old to ninety-years-old and determinedly walking with a cane.