NEW YORK — The mass shooting at a Parkland, Fla., high school, which killed 17 students and staff, and sparked nationwide student-led marches for gun control, was the top news story of 2018, according to The Associated Press’ annual poll of U.S. editors and news directors.

The No. 2 story was the investigation by special counsel Robert Mueller into whether Donald Trump’s election campaign coordinated with Russia. It was one of several major stories — in a year jam-packed with dramatic developments — in which the U.S. president played a role.

A year ago, the surge of #MeToo sexual misconduct allegations that toppled many powerful men was voted the top news story of 2017. The continuing momentum of #MeToo in 2018 was this year’s No. 3 story.

Here are 2018’s top 10 stories, in order:

Parkland shooting: It happened on Valentine’s Day — an act of senseless hate by a gunman with a semi-automatic rifle who killed 14 students and three staff members at Marjory Stoneman Douglas High School. Previous mass shootings had prompted passionate calls for tighter gun-control laws, but this time was different. A group of student survivors at the school, soon joined by allies nationwide, launched the March for Our Lives movement that organized massive walkouts and peaceful protests at schools across the country. The movement remains active, and has helped energize the broader campaign for tougher gun laws.

Trump-Russia probe: Throughout 2018, Mueller’s team investigated whether Trump’s campaign colluded with Russia ahead of the 2016 election and whether the president obstructed the investigation. The evidence shows a broad range of Trump associates had Russia-related contacts during the campaign and transition period; some former Trump aides have been indicted for lying to the FBI.

#MeToo: The #MeToo movement, which surfaced late in 2017, maintained its momentum throughout 2018 as many more powerful men were forced to account for past instances of sexual assault and misconduct. Once-revered comedian Bill Cosby was sentenced to prison; so was Larry Nassar, the former Michigan State and USA Gymnastics sports doctor convicted of molesting hundreds of young women. Disgraced Hollywood mogul Harvey Weinstein was charged with rape. And Les Moonves was ousted as top executive at CBS after a dozen women accused him of sexual misconduct.

Mass shootings: When a Marine combat veteran shot dead 12 people at a country music bar in California in November, it was a grim “Not again” moment for many Americans — the fifth mass shooting of the year in the U.S. that produced nationwide shock and sorrow. In May, two months after the Parkland shooting, eight students and two teachers were killed at a high school in Santa Fe, Texas. In June, a gunman shot dead five employees at the Capital Gazette newspaper in Annapolis, Md. And in October, 11 people were killed at the Tree of Life synagogue in Pittsburgh during Shabbat morning services.

U.S. midterm elections: With Donald Trump on the minds of many voters, Democrats managed to flip about 40 seats in the House of Representatives to seize control of that chamber from Republicans. But the GOP boosted its slim majority in the Senate and will have a 53-47 edge in the next session of Congress.

U.S. immigration: Events along the U.S.-Mexico border produced yearlong drama and controversy. At the height of the midterm election campaign, Trump deployed thousands of Army troops to the border, warning of threats from a caravan of migrants who’d journeyed from Central America. Earlier, a zero-tolerance order from Trump resulted in more than 2,500 migrant children being separated from their families. The practice sparked global outrage from politicians, humanitarians and religious groups; images of weeping children and anguished parents were splashed across newspapers and television.

Kavanaugh hearings: Trump nominee Brett Kavanaugh was narrowly confirmed to fill a vacancy on the U.S. Supreme Court after explosive Senate hearings on allegations of sexual harassment and assault stemming from his high school and college years. While millions of Americans watched on TV, senators heard testimony from Kavanaugh, who denied any wrongdoing, and accuser Christine Blasey Ford, who said he attempted to rape her during a party when they were in high school. Kavanaugh’s presence on the high court gives its conservative bloc a 5-4 majority.

California wildfires: The most populous state endured an epic year for wildfires, culminating with devastating November fires occurring simultaneously 450 miles apart. The Camp Fire in Northern California swept through the city of Paradise, killing at least 86 people — the deadliest U.S. wildfire in a century. Nearly 14,000 homes and hundreds of businesses were destroyed. In Southern California, three people died and 1,500 structures were destroyed by the Woolsey Fire.

Climate change: Worsening natural disasters around the world intensified the focus on climate change; delegates at a global summit in Poland negotiated an agreement on the next steps to minimize harm. In the U.S., a government report warned of devastating impact, prompting pushback by Trump.

Khashoggi killing: For weeks, Saudi authorities issued a variety of denials. But eventually it became clear that Washington Post columnist Jamal Khashoggi was killed on Oct. 2 inside the Saudi Consulate in Istanbul. Khashoggi, a native of Saudi Arabia, was fiercely critical of its royal regime and the Saudi role in the catastrophic war in Yemen. The murder has had major diplomatic repercussions, in part because of widespread belief that Saudi Arabia’s powerful crown prince, Mohammed bin Salman, was involved. The U.S. Senate passed a measure blaming the crown prince for the death, a move opposed by Trump as he tries to preserve close U.S.-Saudi ties.