OPINION: Gun controls will be the first to change. Prime Minister Jacinda Ardern has already made that a touchstone of the Government's response to the outpouring of grief, horror and shock over Friday's shootings in Christchurch.
So it will happen, and it will happen quickly.
Cabinet will take the first steps on Monday, and if we assume they follow Australia's example after the Port Arthur massacre, we can expect announcements within days, though legislative changes will take longer.
Attorney General David Parker has already flagged a ban on semi-automatic weapons, and briefed Ardern on Sunday morning, so we can assume that will be one of the proposals on Cabinet's agenda.
New Zealand's gun laws are among the loosest in the world and efforts to overhaul them have been bogged down in argument for years. Up till now, there has been little political will to change the law. But there will be even less political will to block change now, in the days immediately following the death of at least 50 innocent mosque-goers. Coalition ally NZ First could balk at sweeping controls, however.
The ripples from Friday's shooting will go even wider, however.
In the immediate aftermath of the shooting, while we were all grieving, there was no place for recriminations, especially with so many heroes to thank - like the mosque caretaker who tackled the shooter and drove him off, the victims who threw themselves in front of others to shield them, and the police officers who took the alleged shooter Brenton Tarrant down. They were acts of extreme bravery.
But Ardern has already asked questions of our intelligence agencies about the Australian who managed to slip under everyone's radar, despite his extremist ideology, and his accumulation of a cache of high powered weapons.
Those questions will grow louder and more demanding over the coming days.
Australian and New Zealand officials have said Tarrant was not under watch in either country, and had never come to the attention of police.
But criminality has never been the only trigger for coming to the attention of the intelligence agencies; violent, and extremist ideology is also a red flag.
Christchurch's ugly underbelly has long been its white supremacist gangs, and while Tarrant only moved there recently from Dunedin there will be questions about whether any of that movement's members are among the 30 to 40 people on the SIS watch-list. Or did the string of Isis related attacks internationally - from Paris, to Belgium, Australia, Denmark and France to name just a few - shift everyone's attention elsewhere?
The Tarrant case also raises questions about the huge Five Eye's electronic surveillance system, which is supposed to detect terrorism and other threats.
Our own Government Communications Security Bureau is the fifth eye in that arrangement, which also includes the United States, Britain, Australia and Canada.
The mosque shooting showed how little the US and its allies share intelligence on domestic terrorism threats, according to The Washington Post.
In 2013 a law change permitted the Government Communications Security Bureau to monitor New Zealanders if national security issues are at stake, but the Security Intelligence Service and police are still the lead agencies for detecting and monitoring domestic threats.
A merger of SIS and GCSB has always been politically unpalatable and would likely still be hugely unpopular.
But an inquiry into how our various intelligence arms managed to miss Tarrant seems inevitable given the catastrophic consequences.
The graphic way in which way the shooting played out on social media and quickly went viral has also horrified the world and will equally demand a response.
The tech giants like Facebook and You Tube have been heavily criticised for the length of time it took to take down a graphic video of the killings.
Ardern confirmed on Sunday evening that among the calls of condolence was Facebook chief operating officer Sheryl Sandberg, who Ardern has met previously.
Parker, in his role as Attorney General has been talking about reining in the tech giants - and in what turns out to be a highly prescient speech on Thursday, a day before the shootings, gave notice of his thinking when addressing a group of judges.
He posed the question "what duties were owed by those who "profit from social media platforms to society, private citizens, or to the public institutions which democracy relies upon? "
Rule changes in the social media arena may not come as swiftly as gun controls, but we can expect the Government will eventually put the blow torch on the tech giants as well.
There will be other ripples, some of them political. Ardern's response to the tragedy has been composed, steely and compassionate. She has presented a face to the world that is how New Zealand wants to be seen.
Like John Key before her, in his response to the Christchurch earthquakes, Ardern's leadership has been immeasurably strengthened by her handling of a major crisis.
But New Zealand's belief in itself as one of the world's safe havens has been badly shaken.
Reverberations from the shooting have been amplified by the fact that is how the rest of the world sees us as well.
And the ripples from losing that could potentially be the most lasting.