This is a cancer that metastasized long ago. Regardless, the fight to save the patient must go on because there is no other moral choice.

After decades of escalating terroristic violence, it seems there is no amount of mayhem, no tragic sacrifice of innocent lives that can shock us. As always happens when youths become the primary victims, this episode comes close.

The suicide bombing outside an arena in Manchester, England, killed people exiting the venue, including kids heading to meet parents at a pickup point. The concert was by American pop star Ariana Grande, who built her young fan base as character on a hit TV show before branching out into a solo career.

The point is that this hideous attack could have happened anywhere within the reach of popular culture, including Hawaii, and at any time. By chance, it happened in the U.K., as President Donald Trump was starting the European leg of his inaugural international trip, just after stops in Saudi Arabia and Israel.

There, in the midst of dealmaking, terrorism was a key focus for talks. Almost immediately, the president had to confront the bloody reality.

The world has become almost inured to relentless violence; still, in his remarks, Trump did not want to empower the attacker. Larger-than-life epithets such as “monsters” were discarded in favor of the term “evil losers.”

Critics might have taken issue with such a lightweight characterization but in fact, the description is not far off the mark. Those who are attracted to this kind of criminality are often those who have failed and feel dispossessed. Salman Abedi, the 22-year-old man deemed responsible for the Manchester killings, was described variously as being quiet and respectful … and very angry.

The imam in the attacker’s own mosque said that Abedi had shown him the “face of hate” after a talk warning against terrorism. Within British security circles, Abedi was not particularly high on anyone’s radar, and yet, unobserved, the Manchester-born citizen returned from a visit to Libya and hatched his murderous plan.

How many people are there like him, filled with resentment and precious little hope, fueled by propaganda that circles the globe in an instant? The cancer of hate has spread to the four corners of the globe, and it only takes one person to wreak this kind of havoc.

Many thousands of miles away in this remote island state, Hawaii residents have no immunity from violence. Despite this fact, the feeling has prevailed that issues of terrorism, in farflung countries, do not afflict this place.

That sense of insularity has been shaken.

The looming threat of North Korea becoming a nuclear power worries isle residents. Hawaii, long weary of security crackdowns, now can easily foresee a more militarized environment returning.

And recently the sense of vulnerability intensified further, when the erratic behavior of an American Airlines passenger, Anil Uskanli, compelled two military fighter jets to escort the plane to a Honolulu safe landing. It’s unknown whether Uskanli, bound for a mental health evaluation, ever would have carried out an attack. But terroristic thoughts are always present, Uskanli told the FBI.

There plainly is cause for vigilance here: Extremist idealogy won’t be eradicated any time soon.

For the longer term, the Muslim community must persist with anti-violence messaging, as Abedi’s imam and others have done.

And the Saudis, among those who have funneled financial aid to those preaching extremism, must be prevailed upon to end that practice.

Unfortunately, the Trump transactional approach — the Saudi arms deal furthered his jobs agenda — backtracks from that aim. Americans should hope that behind the scenes, the U.S. is still pushing strongly for peace in a world where, sadly, the sickness of war has set in.