More than 100,000 ordinary moms will spend this Mother’s Day at the Mall–as in Lincoln and Jefferson, not Baby Gap. Even more–perhaps a million in all–will march in local demonstrations against gun violence in more than 60 cities. Their message to Congress: give us new gun laws, or suffer in November. The emergence of guns as a key issue for suburban women–“soccer moms” like Betsy Storm–marks a pivotal moment for the gun-control movement. And it could be a major challenge for George W. Bush, who spent much of last week trying to explain his friendship with the National Rifle Association while Al Gore hammered away at him. The country is still divided over whether new gun laws are needed, but a Pew Research poll last month found that 66 percent of Americans–and 73 percent of women–think gun control is more important than gun rights. This time, unlike election years past, it may just be the one issue that decides their votes.

It used to be that suburban moms rallied over abortion rights or public education, but not gun violence; most of that was confined to the cities. The school shootings changed all that. Donna Dees-Thomases, a 42-year-old mother of two, reached her breaking point when she watched the footage of small children running from their Granada Hills, Calif., day-care center last August. A week later Dees-Thomases–the sister-in-law of Clinton friend Susan Thomases–applied for a permit for 10,000 people to march on the Capitol.

The idea caught on, boosted by celebrities like Rosie O’Donnell, and a hastily assembled Web site. (Never mind that the first home page accidentally featured a photo of the Supreme Court rather than the Capitol.) The marchers have sold more than $100,000 in T shirts off the Web, at $25 each, and 13 cities have scheduled their own marches in the last two weeks. In the San Francisco Bay Area, working mothers find time to plan by logging onto the Web from 9 p.m. to midnight. In a Sacramento retirement home, women in their 80s have signed on to take a bus to the nearest rally.

Not all mothers have rallied. A lot of black moms in the inner cities resented the sudden passion of white suburban women–after decades of urban killings that garnered little outrage. Dees-Thomases and her organizers won some of them over by apologizing up front. Last fall Dees-Thomases called New York Police Lt. Eric Adams, leader of a group calling itself 100 Blacks in Law Enforcement Who Care, after she saw him on TV. She told Adams that her suburban moms needed to “atone” for not speaking out earlier. “Better late than never,” Adams said. His group sponsored a bus.

The march has run into more entrenched opposition from women who feel safer with handguns in their purses, and from a lot of families who don’t think gun foes have a monopoly on motherhood. Women calling themselves the Second Amendment Sisters will stage their own march on Mother’s Day. “These women are not speaking for us,” says Alice Rainey, a 59-year-old Illinois mother. “Our kids have been around guns all their lives. It’s part of their heritage.”

The moms’ demands–a list of “common sense” laws–was lifted directly from anti-gunners, who are paying most of the bills for the march’s office space and outreach. Gun-control groups hope to pit ordinary moms against the bogeyman of the NRA–and its allies on the Republican ticket. Last week Handgun Control gleefully released tapes of an NRA official, Kayne Robinson, saying that if Bush is elected, “We’ll have… a president where we work out of his office.” Robinson also cited Bush’s “unbelievably friendly relations” with the gun lobby. Bush said he’d be his “own man” in the White House, but the episode left him caught between crucial swing voters and a key Republican constituency–exactly where the gun foes want him to be.

Even if it falls short of expectations, the Million Mom March could prove troubling for the gun lobby. The planning involved in getting 600 buses to Washington has almost overnight given gun foes something they’ve never had: a base of grass-roots activists who’ve got the time to get out the vote. The day after the march, Dees-Thomases will announce a new group that will keep the moms’ network intact. They’ll probably be called on to help get out the vote in the fall–just as their kids are headed back to school.