WASHINGTON (AP) — Summoned by student survivors of the Florida school massacre, tens of thousands of people poured into the nation’s capital and cities across America on Saturday to march for gun control and ignite political activism among the young.Organizers of the “March for Our Lives” rally in Washington hoped their protest would match in numbers and spirit last year’s women’s march, one of the biggest Washington protests since the Vietnam era and one that far exceeded predictions of 300,000 demonstrators.Bearing signs reading “We Are the Change,” ”No More Silence” and “Keep NRA Money Out of Politics,” protesters lined Pennsylvania Avenue from the stage near the Capitol, stretching back toward the White House. The route also takes in the Trump International Hotel.President Donald Trump was in Florida for the weekend. A motorcade took him to his West Palm Beach golf club in the morning.Large rallies also took shape in such cities as Boston, Houston and Parkland, Florida, the site of the Feb. 14 shooting at Marjory Stoneman Douglas High School that left 17 people dead.The police presence was heavy as more than 20,000 people filled a park near the school, chanting slogans such as “Enough is enough” and carrying signs that read “Why do your guns matter more than our lives?” and “Our ballots will stop bullets.”Gun violence was fresh for some in the Washington crowd: Ayanne Johnson of Great Mills High School in Maryland held a sign declaring, “I March for Jaelynn,” honoring Jaelynn Willey, who died Thursday two days after being shot by a classmate at the school. A boy was injured in the attack, and the shooter died.Since the bloodshed in Florida, students have tapped into a current of gun control sentiment that has been building for years – yet still faces a powerful counterpoint from the National Rifle Association and its supporters.Organizers hope the passions of the crowds and the under-18 roster of speakers will translate into a tipping point starting in the midterm elections this year.The protesters, many of them high school students, claim that the youth leadership of this initiative is what will set it apart from previous attempts to enact stronger gun-control legislation.Polls indicate that public opinion nationwide may be shifting on an issue that has simmered for generations, and through dozens of mass shootings.A new poll conducted by The Associated Press-NORC Center for Public Affairs Research found that 69 percent of Americans think gun laws in the U.S. should be tightened. That’s up from 61 percent who said the same in October 2016 and 55 percent when the AP first asked the question in October 2013. Overall, 90 percent of Democrats, 50 percent of Republicans and 54 percent of gun owners now favor stricter gun control laws.But even with claims of historic social momentum on the issue of gun control, the AP poll also found that nearly half of Americans do not expect elected officials to take action.Among the questions facing march organizers and participants will be how to translate this one-day event into legislative change.One way they hope to do that is by registering young voters and channeling energy into the midterm congressional elections this fall.