The CP USA joined with hundreds of other organizations: labor, youth, peace, justice, clergy, political organizations and international groups, in the largest climate march ever.
So in this year's November 4 midterms, the question is once more whether the Democrats can turn out enough voters.
"The tea party Republicans divide the country: Scaring people is not standing up for people."
Generating some of the most excitement were activists from other nations who stood in solidarity with their peers.
"This march represents an incredible diversity of people, all realizing that this is the same fight."
Pulling together, volunteering and pitching in when city leaders seemed unable or unwilling to - just added to the unity building during a time of profound crisis.
The pro-Darren Wilson folks were screaming rage-soaked insults, but the protestors stoically chanted back in unison.
"The people in this crowd should have this amazing view: It's a sea of people of every culture and heritage coming together for change."
But even as the San Diego Labor Council hailed the new measure, it warned about an underhanded petition to undermine it.
"Working people will suffer disproportionately from the current patterns of investment and neglect that do not prioritize good jobs, clean air, and healthy communities."