We enter a new round of the too-familiar conversation about gun control in America that follows each mass shooting. Many outsiders (and some insiders) may be baffled as to how this keeps happening. Why don’t they pass a law to bring the US into line with the rest of the world? Are they stupid? Are they crazy? Are the politicians corrupt?

The simple fact is that for those strongly committed to gun ownership rights in America — and that is a lot of people — periodic mass shootings are a price worth paying to maintain this. Of course, they wouldn’t use that crass language, but it is their underlying position.

At this point, it is trivially obvious that tighter gun control would reduce incidences of mass shooting and other gun violence. But this isn’t really the heart of this debate. There is a trade-off to be made between one particular individual right and wider public safety — and at present the American public’s elected representatives, usually reflecting views of the people that put them in office, land in a very different place than those in almost all other countries.

Present interpretation of the 2nd Amendment of the US Constitution makes blanket national bans on the individual right to own a gun a legal non-starter in the US. The courts would strike it down as unconstitutional, as surely as the sun will rise tomorrow. Given the need to legislate within limits imposed by the Constitution and Supreme Court precedent, any measures proposed after a particularly shocking incident rarely go far enough to have any effect on the event to which they are responding. So conservative defenders of gun rights can simply say — as they did on Thursday, after the murder of 17 teenagers in a Florida high school — “Your new law won’t stop the killing, anyway.”

Even if the courts were not in the way, there is no legislative majority in Congress for significant gun control, and little prospect of one in the foreseeable future. That is because of the National Rifle Association, as commonly asserted, but it is not just because of the NRA’s massive campaign contributions — this is not as simple as trading votes for money. Far more important is the NRA’s role in using its large membership and well-resourced communications and networks to mobilize voters who strongly oppose any legislation.

Yes, opinion polling finds majorities of the general population in favour of tighter firearm restrictions. The problem is that the minority who oppose them consider gun rights a high-priority issue, often the highest. If you are an elected official and you are not NRA-certified as a firm defender of gun rights, in many districts and states you will almost certainly lose your party’s nomination for the next election.

In contrast, among those who favor new gun restrictions, the issue rarely determines their vote in a party primary, let alone a general election. The hard truth is that, when the headlines pass after an incident, many will have other priorities than gun control.

High-casualty mass shootings are the most visible form of gun violence. They are more frequent, but they are still uncommon and represent only a small portion of annual gun deaths, especially when suicides are included in the toll. So conservatives will resist allowing these incidents to set the terms for the debate.

If Sandy Hook, Las Vegas, and Orlando didn’t move the dial on public opinion enough to reshape the electoral and legislative calculus, neither will Marjory Stoneman Douglas High School. Part of this is constitutional. Part of this is institutional and party political. Part of this is cultural.

And part of this is that few care enough, long enough — when compared with the challenge of an anti-gun control movement which will always care and fight for their “rights” — to make the change.