Organizers' fears aren't simply directed at Washington: Last month CBS News national security correspondent David Martin reported on, as a sign of concern over Iran's nuclear program - and Israel's efforts to prod the United States to do more, even militarily, to halt it.
Sara Flounders, national coordinator of the Stop War in Iran coalition, said the anti-war movement's message had gained traction given the costs the Iraq War has imposed upon our economy.
"This is a nerve that we've really struck," she told CBS News. "The threat of a new war in Iran at a time of economic hardship in the U.S. - and there isn't even enough to pay for disabled veterans!"
Saber-rattling has been intensifying in recent months as talks between Iran and Western nations over Tehran's nuclear efforts have failed to secure for the West its goal of an end to Iran's uranium enrichment program.
Last December two encounters in the Straits of Hormuz between Iranian vessels and U.S. Navy ships grew heated, with, and not without some suspicions - from the Navy Times, no less - that .
Meanwhile, having to resort to Photoshop.in a show of strength that someone in Iran's state media didn't think was impressive-looking enough without
Ardeshir Ommani of the American-Iranian Friendship Committee who joined in today's demonstrations told CBS News that in recent trips to Iran, "I talked to people in all walks of life, and they all said, 'Can you tell the American people that we don't want war? We haven't done anything to the United States.'
"They thought I had an in-road to the powers-that-be!"
Ommani, who came to the United States 45 years ago, said he has protested wars since Vietnam, but that the Iraq War in particular stirred his activism. He fears now another war in the region. "Iran has become the central focus of George W. Bush and the Pentagon," he said.
Earlier this month, Seymour Hersh, a journalist for The New Yorker who has written on the United States' clandestine efforts against Tehran, told a Campus Progress journalism conference that officials attending a meeting in Vice President Cheney's office had discussed ideas on how to provoke conflict between the U.S. and Iran by instigating an incident that would garner support from the American public.
One idea proferred, Hersh said, was, "Why don't we build - we in our shipyard - build four or five boats that look like Iranian PT boats, put Navy SEALs on them with a lot of arms, and next time one of our boats goes to the Straits of Hormuz, start a shoot-up?"
It was rejected, Hersh said, because "You can't have Americans killing Americans. That's the level of stuff we are talking about.
"Silly? Maybe. But potentially very lethal."
In addition to anti-war marches, today also marked the deadline for Iran to demonstrate it will stop expanding its nuclear enrichment program or face further sanctions.
In a statement posted Saturday on an Iranian government Web site, President Mahmoud Ahmadinejad said that.
Press Secretary Dana Perino says the U.S. will consult with its allies on the Iranian statement.
Perino, who had earlier warned of "negative consequences" if Iran rejected the U.S. offer, said, "It's a shame that Iran does not take us up on our generous incentives package."
CBS News White House Correspondent Peter Maer, who is in Kennebunkport, Maine, where Mr. Bush is vacationing, said the president will be briefed on the response.
Protesting The Cloud Of War Under A Cloud Of Rain
Among the 90 cities where protests were being held this weekend were Los Angeles, Salt Lake City, Fairbanks, Ak., Washington, D.C., Miami, Atlanta, Chicago and Raleigh, N.C.
In New York City, an estimated 200 participants assembled in Times Square amidst heavy rain and a counter-protest of a couple dozen Bush supporters.
[please insert color / quotes from march here ]
Within sight of Walker's Point, peace activist Laurie Dobson called for a moment of silence "for all the people this man has killed in his two terms in office."
Then Carlos Arredondo spoke of the loss of his son, Marine Lance Cpl. Alexander Arredondo, who was killed in Iraq on Aug. 25, 2004.
Then the group turned away.