The country has long endured a numbing succession of mass shootings at schools, places of worship and public gathering places.

None forced Congress to react with significant legislation — until now.

Last month, a white shooter was accused of racist motives in the killings of 10 Black people in a supermarket in Buffalo, New York.

Another gunman killed 19 students and two teachers at an elementary school in Uvalde, Texas.

The slayings of shoppers and school children just 10 days apart — innocents engaged in everyday activities — helped prompt a visceral public demand for Congress to do something, lawmakers of both parties say.

Bargainers produced a bipartisan gun violence bill that the Senate is moving toward approving later this week, with House action expected sometime afterward.

Here’s a look at the confluence of factors that helped to produce a compromise.

This is an election year. Republicans are favored to take over the House, now narrowly controlled by Democrats, and have a solid chance of capturing the 50-50 Senate.

To reinforce their chances, Senate Minority Leader Mitch McConnell, R-Ky., knows they need to attract moderate voters like suburban women who will decide competitive races in states like Arizona, Georgia, Nevada and North Carolina.

Taking steps aimed at reducing mass shootings helps the GOP demonstrate it is responsive and reasonable — an image tarnished by former President Donald Trump and the hard-right deniers of his 2020 election defeat.

Underscoring the focus he prefers, McConnell lauded the gun agreement by pointedly telling reporters Wednesday that it takes significant steps to address “the two issues that I think it focuses on, school safety and mental health.”

The bill would spend $8.6 billion on mental health programs and over $2 billion on safety and other improvements at schools, according to a cost estimate by the nonpartisan Congressional Budget Office. The analysts estimated its overall cost at around $13 billion, more than paid for by budget savings it also claims.

But it also makes the juvenile records of gun buyers aged 18 to 20 part of background checks required to buy firearms, bars guns for convicted domestic abusers not married to or living with their victims and strengthens penalties for gun trafficking. It finances violence prevention programs and helps states implement laws that help authorities temporarily take guns from people deemed risky.

The measure lacks stronger curbs backed by Democrats like banning the assault-style rifles used in Buffalo, Uvalde and other massacres and the high-capacity ammunition magazines those shooters used.

Senate Majority Leader Chuck Schumer, D-N.Y., said Wednesday that this time, Democrats decided they would not “hold a vote on a bill with many things we would want but that had no hope of getting passed.” That’s been the pattern for years.

Democratic Sens. Chris Murphy of Connecticut and Kyrsten Sinema of Arizona, and Republican Sens. John Cornyn of Texas and Thom Tillis of North Carolina, led negotiators in talks that lasted four weeks.

Their accord is Congress’ most important gun violence measure since the now-expired assault weapons ban enacted in 1993.