While the rest of America took time to celebrate the sacrifices of veterans and their families on Memorial weekend, 500 San Francisco protesters marched against Monsanto Corporation, carrying signs and chanting, “Evil Seed of Corporate Greed.”

Calling themselves a coalition representing beekeepers, physicians, organic farmers, preschool teachers, butterflies, and parents of autistic kids, the festively dressed gaggle blew whistles and pounded drums as they marched from Justin Herman Plaza down the Embarcadero to Fisherman’s Wharf, demanding an end to genetically modified food labeling laws, a global ban on Monsanto’s Roundup herbicide and other changes in the way Monsanto operates. A good time was had by all in the 65 degree weather.

Protesting genetically modified organisms (GMO) in California peaked in 2012, when the state’s voters turned back Proposition 37 on the November ballot.

The initiative sought to require “Mandatory Labeling of Genetically Engineered Food,” referred to by the propositions sponsor as “Frankenfoods.” Author James Wheaton called his Prop 37 the “California Right to Know Genetically Engineered Food Act.” But his initiative was much more complex than just: 1) requiring labeling on raw or processed food offered for sale to consumers if the food is made from plants or animals with genetic material changed in specified ways; 2) prohibiting labeling or advertising such food as “natural”; 3) exempting from this requirement foods that are “certified organic or unintentionally produced with genetically engineered material or sold for immediate consumption such as in a restaurant; or alcoholic beverages.”

Six weeks before the vote, the California Democratic Party-backed initiative was favored in the USC/Los Angeles Times poll by 61 percent and opposed by only 25 percent.

But then a coalition of the California Republican Party, farmers and agribusinesses pointed out that Proposition 37 was a 1) deceptive, deeply flawed food labeling scheme that would add more government bureaucracy and taxpayer costs, create new frivolous lawsuits, and increase food costs by billions–without providing any health or safety benefits; 2) full of special interest exemptions; and 3) authorized shakedown lawsuits.

The initiative was so flawed that the usually reliably liberal Los Angeles Times and Sacramento Bee led over 30 newspapers around the state in opposing the initiative so sloppily written that it contained language that “could be construed by the courts to imply that processed foods could not be labeled as ‘natural’ even if they weren’t genetically engineered.” The newspapers also warned that “mom-and-pop groceries” would be wiped out from lawsuits, and food costs could jump.

Three weeks before the election, polling by the California Business Roundtable revealed the “For” support had dropped to 48.3 percent and the “Against” opposition had leaped to 40.2 percent.

With the public convinced by Election Day that the initiative would cause substantial increases in food costs, Proposition 37 lost by a margin of 50.4 percent against to 48.6 in support. The reversal of support devastated the coalition of environmentalists and organic farmers that overplayed their hand in trying to grab power.

Three years later, the anti-GMO crowd seems to finally be trying to revive the movement. Protestors on Saturday indicated they were focusing on opposing a bill in Congress that could eliminate states’ rights to pass GMO labeling laws and were objecting to Monsanto’s continuing sale of “Roundup” because it contains a possible carcinogen called glyphosate.

In a statement, Monsanto spokeswoman Charla Marie Lord said that the company’s 22,000 workers are “committed to having an open dialogue about food and agriculture.” She emphasized that studies show glyphosate can be safe if used properly.