The coalition was loose, with some opponent groups focused on opposition to WTO policies (especially those related to free trade), with others motivated by pro-Labor, anti-Capitalist, or environmental agendas. Many of the NGOs represented at the protests came with credentials to participate in the official meetings, while also planning various educational and press events. The AFL-CIO, with cooperation from its member unions, organized a large permitted rally and march from Seattle Center to downtown.
Others, however, were more interested in taking direct action including both civil disobedience and acts of vandalism and property destruction to disrupt the meeting. Several groups were loosely organized together under the Direct Action Network (DAN), with a plan to disrupt the meetings by blocking streets and intersections downtown to prevent delegates from reaching the Washington State Convention and Trade Center, where the meeting was to be held.
As a token of the effectiveness of democratic lobbying at local level, Seattle declared itself an MAI Free-Zone by unanimous vote in the City Council on Monday, April 12, joining numerous cities both in the US and around the world.
On 12 July, the Financial Times reported that the latest United Nations Human Development report advocated "principles of performance for multinationals on labour standards, fair trade and environmental protection. . . needed to counter the negative effects of globalisation on the poorest nations". The report itself argued that "An essential aspect of global governance is responsibility to people — to equity, to justice, to enlarging the choices of all".
On 16 July, Helene Cooper of the Wall Street Journal warned of an impending "massive mobilization against globalization" being planned for the end-of-year Seattle WTO conference. Next day, the London Sunday Independent savaged the WTO and appeared to side with the organisers of the rapidly developing storm of protest:
The way it has used [its] powers is leading to a growing suspicion that its initials should really stand for World Take Over. In a series of rulings it has struck down measures to help the world's poor, protect the environment, and safeguard health in the interests of private—usually American - companies.
"The WTO seems to be on a crusade to increase private profit at the expense of all other considerations, including the well-being and quality of life of the mass of the world's people," says Ronnie Hall, trade campaigner at Friends of the Earth International. "It seems to have a relentless drive to extend its power.
On November 16, a fortnight before the conference, President Clinton issued Executive Order 13141—Environmental Review of Trade Agreements which committed the United States to a policy of "assessment and consideration of the environmental impacts of trade agreements." This was a surprise to the negotiators of the developed nations and corporate sector, but an endorsement of the criticisms of the Third World and non-government organizations (NGOs) bent on blunting the perceived ambitions of the Millennium Round's hopeful promoters.
On the morning of November 301999, the Direct Action Network's plan was put into action. Several hundred activists arrived in the deserted streets near the convention center and began to take control of key intersections. Over the next few hours, a number of marchers began to converge on the area from different directions. These included a student march from the north and a march of citizens of the developing world who marched in from the south. Some demonstrators held rallies, others held teach-ins and at least one group staged an early-morning street party. Meanwhile, a number of protesters still controlled the intersections using lockdown formations.
The control of the intersections, plus the sheer numbers of protesters in the area, prevented delegates from getting from their hotels to the Convention Center. It also had the effect of cutting the police forces in two: the police who had formed a cordon around the convention center were completely cut off from the rest of the city. The police outside of the area eventually decided to attempt to break through the protesters' lines in the south.
That morning, the King County Sheriff's Office and Seattle Police Department fired pepper spray, tear gas canisters, percussion grenades, and eventually rubber bullets at protesters at several intersections in an attempt to reopen the blocked streets and allow as many WTO delegates as possible through the blockade. At 6th Avenue and Union Street, the crowd threw them back.
The situation was complicated around noon, when black-clad anarchists (in a formation known as a black bloc) began smashing windows and vandalizing storefronts, beginning with Fox's Gem Shop. This produced some of the most famous and controversial images of the protests. This set off a chain-reaction of sorts, with additional protesters pushing dumpsters into the middle of intersections and lighting them on fire, police vehicles turned-over, non-black-blockers joining in the property destruction, and a general disruption of all commercial activity in downtown Seattle.
Other protesters attempted to physically block the activities of the black bloc. Seattle police, led by Chief Norm Stamper, did not react immediately, however, because they had been convinced by protest organizers during the protest-permit process that peaceful organizers would quell these kinds of activities.
The police were eventually overwhelmed by the mass of protesters downtown, including many who had chained themselves together and were blocking intersections. Meanwhile, the late-morning labor-organized rally and march drew tens of thousands; though the intended march route had them turning back before they reached the convention center, most ignored the marshals and joined what had become a street-carnival-like scene downtown.
Over 600 people were arrested over the next few days. One particularly violent confrontation occurred the evening of November 30, when police pursued protesters fleeing from downtown into the bohemian neighborhood of Capitol Hill, using tear gas, pepper spray, and physical force. A police order that day also banned the use or sale of gas masks downtown, provoking criticism.
The Seattle City Council also dispelled these rumors with its own investigation findings:
"The level of panic among police is evident from radio communication and from their inflated crowd estimates, which exceed the numbers shown on news videotapes. ARC investigators found the rumors of "Molotov cocktails" and sale of flammables from a supermarket had no basis in fact. But, rumors were important in contributing to the police sense of being besieged and in considerable danger."
An editorial in The Nation disputed Molotov cocktails have ever been thrown at an anti-globalization protest within the US.
Similar tactics, on the part of both police and protesters, were repeated at subsequent meetings of the WTO, IMF/World Bank, Free Trade Area of the Americas, and other international organizations, as well as the Democratic and Republican National Conventions in the U.S.
To many in North American anarchist and radical circles, the Seattle WTO riots, protests, and demonstrations were a success and are thought of as the most recent victories in the U.S. Prior to the "Battle of Seattle," there was almost no mention of "anti-globalization" in the US media, while the protests are seen as having forced the media to report on why anybody would oppose the WTO. However, this was only the second phase of these mass demonstrations. The first began on 12 December 1997 in which newly formed grass-roots organizations blockaded Melbourne, Perth, Sydney and Darwin city centers.
On January 16, 2004, the city settled with 157 individuals arrested outside of the no-protest zone during the WTO events, agreeing to pay them a total of $250,000. On January 30, 2007, a federal jury found that the City of Seattle had violated protesters' Fourth Amendment constitutional rights by arresting them without probable cause or hard evidence.
The massive size of the protest pushed the city of Seattle $3 million over their estimated budget of $6 million, partly due to city cleanup and police overtime bills. In addition, the damage to commercial businesses from vandalism and lost sales has been estimated at $20 million.