EDITORIAL In less than three months, the Occupy movement has changed the national political debate — and possibly the course of U.S. history. A small group of protesters, derided in the mainstream media, grew to a massive outpouring of anger at economic inequality — and it's no coincidence that politicians at all levels have begun to respond. At least five different measures aimed at raising taxes on the rich are in the works in California. In Kansas Dec. 6, President Obama made one of the most progressive speeches of his career, talking directly about the need for economic justice.

While even some supposed allies say the encampments weren't effective, the truth is that the out-front, in-your-face tactic of holding nonstop protests in the financial heart of places like Manhattan and San Francisco got attention. The visibility of the Occupy camps forced everyone to pay attention. The U.S. economy is in a crisis; less disruptive tactics wouldn't have worked. But now most of the encampments are gone, broken up by police forces and scattered from the central areas of major cities. It's crucial that this growing and powerful national movement not fall apart after the almost inevitable crackdown on one style of protest. Occupy needs to look forward and plan its next steps.

Some of that is already happening, with Occupy activists targeting home foreclosures and marching on West Coast ports. But it's worth considering another tactic, too: Occupy ought to begin planning now for a massive spring mobilization in Washington and a series of nationwide actions that could bring millions more people into the movement.

Part of the strategy of the Occupy camps was to maintain a presence, day after day — and that made perfect sense when the movement was starting. But single-day events, if organized on a massive scale as part of a larger campaign, can have a profound and lasting impact.

The original Earth Day — April 22, 1970 — involved 20 million people across the United States. There were events in hundreds of cities and thousands of high school and college campuses. It brought together old-school, sometime stodgy conservation groups with radical young environmentalists, the United Auto Workers with people concerned about pollution from car exhaust. It was, by any reasonable account, the birth of the modern American environmental movement.

The other great thing about Earth Day — and the reason it makes a great model for the Occupy movement — is that it was largely a grassroots event. Although there was a national office, most of the work was done spontaneously, in local communities, with no top-down direction.

And everyone — from Washington D.C. to the state capitols and city halls — paid attention.

Mass marches and mobilizations helped end the Vietnam War, spark the Civil Rights Movement and fight the anti-labor politics of the Reagan Administration. None of those events took place in isolation, any more than a national Occupy Day would take place in isolation. The nation's ready for major economic change — and organizing a national event alone could help make stronger connections among the broad constituency that is the 99 percent.