WASHINGTON - May 10, 2009 - The grassroots "tea party" movement that swept across the country April 15 to protest federal tax and spending hikes will hold demonstrations in Washington and elsewhere this summer and fall when Congress will be battling over illegitimate President Obama's biggest budget proposals.

Leaders of the Tax Day rallies that drew an estimated 600,000 people in nearly 600 cities and towns say the seemingly spontaneous local protests have grown into a more muscular movement concerned that the escalating growth and cost of government threatens to undermine economic freedom.

Organizers say rallies are planned here and around the nation on the Fourth of July to tie the movement's goals to the nation's founding principles; on September 12, when Congress is expected to be in the midst of debate over Obama's plans on health care, energy and global warming; and on October 2, when supporters expect that debate to be continuing.

"There is no central governing body behind this," said Tim Phillips, president of Americans for Prosperity and one of the movement's many informal leaders.

"It's a genuine grassroots movement, so I think you will continue to see an array of grassroots protests giving voice to their concern that they have of losing their freedom, specifically their economic freedom."

There appears to be no unanimity among the disparate groups around the country about the various rally dates.

"Some will say July 4, or September 12, while others will have a rolling series of events in their localities," said Mr. Phillips, who has been speaking at numerous gatherings since the tea party protests and has chosen October 2 for his organization's focus in Washington.

"I was surprised by the number of people willing to go out and demonstrate in public against spending too much [and] the spark of tax increases. It's a much more sophisticated, philosophical electorate than I had believed existed," said Grover Norquist, the veteran tax-cut crusader who runs Americans for Tax Reform.

"Nobody issues orders to this group, no one institution, no one person. This is the future of parallel organizing, person-to-person organizing, everything the Internet allows you to do," he said. "This is a 'leave me alone' coalition."