A makeshift memorial sits outside Ned Peppers nightclub in the Oregon District entertainment neighborhood, where on Aug. 4 a gunman killed nine people, in Dayton, Ohio, Aug. 14, 2019. Credit: Dan Sewell | AP

During Easter weekend in March 1913, the already-saturated levies holding back the swollen Great Miami River in Dayton, Ohio, finally gave way.

Parts of the city were under 20 feet of water. Families were forced into their attics for safety. Many of these Daytonians sat in the dark, praying for deliverance and vowing that they would help rebuild their city to ensure that such a catastrophe never happened again.

When the water receded several days later, 65,000 people had lost their homes. The coroner listed 92 dead, but estimates of the actual total range as high as 300. “Remember the promises you made in the attic” became the rallying cry of the campaign to rebuild Dayton and construct the comprehensive flood-control system that has held the river back for more than a century.

Today, Dayton is once again confronted by tragedy. On Aug. 4, a gunman opened fire in our crowded Oregon District, a neighborhood of locally owned bars, restaurants and shops. In less than a minute, nine were dead and at least 27 were injured.

As they mourned, Daytonians made clear what they wanted from their elected officials. When Gov. Mike DeWine took the stage at a vigil that evening, people shouted in frustration, “Do something!”

In response, the governor, President Donald Trump and other elected officials, including me, promised action in this time of crisis. We must keep the promises that we have made to try to prevent further tragedies.

The head winds against change are fierce. Some argue that these mass shootings can’t be stopped, except by a good guy with a gun who takes on the bad guy with a gun. Yet in Dayton, there were six good guys with guns — Dayton police officers — just around the corner. Despite their quick response, security video shows that the gunman was still able to kill nine people in about 32 seconds. What more can we ask of first responders?

Others argue that we must solely focus energy on improving mental health care. That is important but deeply inadequate. Research has consistently shown that mental health issues are not the cause of most mass shootings. In any case, there are indications the shooter in Dayton was receiving mental health treatment before the attack.

The common thread among these catastrophic shootings is the easy access to high-powered weapons. Universal background checks, extreme-risk protection orders and limits on assault-style weapons and high-capacity magazines are all overwhelmingly popular policy ideas and would surely save lives.

In Ohio, we are intent on making meaningful progress with common-sense gun laws that I hope will provide an impetus for reforms across the country. So far, many Republicans nationally have refused to take up gun-reform measures — despite the recent carnage in Dayton, El Paso and Gilroy, California — but here in Ohio, our Republican governor has listened to the calls at the vigil to “do something.” He introduced a 17-point plan that includes universal background checks and extreme-risk protection protocols. Dayton’s Republican representative, Michael R. Turner, who had an A rating from the National Rifle Association, has now come out in support of an assault-weapon ban.

As a Democrat, I have no illusions about how difficult it will be to pass DeWine’s proposals in the Republican-controlled Ohio Legislature or to pass similar proposals languishing in Congress. But I am heartened by signs of a bipartisan coalition forming in Ohio and across the country to show that real change is possible.

More than 250 mayors — Democrats, Republicans and independents — signed a letter earlier this month urging Senate Majority Leader Mitch McConnell to take up common-sense reforms. No mayor wants to get the phone call or the middle-of-the-night knock on the door that I did on Aug. 4. I believe that the tragedies in Dayton and El Paso are changing the debate across the nation.

A few weeks ago, 27-year-old Lois Oglesby went to meet friends in the Oregon District — it was her first time out since having her second child a few months earlier. Her celebratory evening abruptly turned to tragedy as the gunman’s shots rang out and struck her.

In her last moments, Oglesby wasn’t thinking of herself, she was thinking of her family. She called her partner, conveying a message that let her children know what they surely already did — that she loved them more than anything.

It now falls on us to build the community that will help bring up Oglesby’s children. We owe it to them to keep the fervent promises we made during a time of crisis. We owe it to them to do something.

Nan Whaley is the mayor of Dayton, Ohio. This column was originally published by The Washington Post.