The Islamic State isn't the first Middle East extremist group to make a gruesome spectacle of kidnapping and killing Westerners. The first wave came in the 1980s, when Hezbollah in Lebanon seized dozens of Westerners amid an anarchic civil war.
But that spree was largely confined to Lebanon and wound down shortly after the country's war ended in 1990. What followed was, by Middle East standards, a comparatively calm decade in the 1990s, when journalists, aid workers and other Westerners could roam with relative freedom around the region.
In retrospect, that was a golden era. For more than a decade now, extremist groups scattered across the Muslim world have been targeting Westerners to such an extent that large swaths of territory are no-go zones, including many parts of Pakistan, Afghanistan, Iraq, Syria, Libya and Yemen.
U.S. aid worker Peter Kassig, also known as Abdul-Rahman Kassig, was the fifth Westerner killed by the Islamic State in recent months, and as with the others, news of his death came via a horrific video.
The collective impact has been dramatic. As the killings and the videos surfaced, U.S. public opinion shifted dramatically in favor of U.S. military action in Syria, something that President Obama had resisted during three years of civil war in Syria.
The visceral response to the killings is likely to have another long-term impact: Western journalists, aid workers, diplomats, businessmen and travelers will steer clear of the most dangerous places for years to come.
"Few charities now operate in Syria and even fewer journalists ... are willing to make the journey into rebel-held Syria. The reason is obvious: No one wants to appear in the next IS video," Shiraz Maher, of the International Centre for the Study of Radicalisation at King's College in London, wrote for the BBC. "The aim is to build and maintain an asymmetric advantage over their enemies. They want us to be afraid — and we are."
Kidnappings In Beirut
Three decades ago, the kidnapping epidemic was centered in Beirut. It was the most Westernized city in the region and a magnet for Americans and Europeans. But it was also home to the newly emergent Hezbollah, a radical Shiite Muslim group backed by Iran. In the space of a few years, Hezbollah carried out dozens of kidnappings, and several of the victims were killed.
News about the hostages was scarce to nonexistent. Associated Press journalist Terry Anderson was held from 1985 to 1991 with barely a word on his condition. But after Anderson and the others were freed, Hezbollah stopped the kidnappings and the period came to an abrupt end.
As an AP reporter working in the Middle East a few years later, I met Hezbollah officials in Beirut in 1996 when the group was in the midst of a brief but intense war with Israel in southern Lebanon. The Islamic group was eager to talk and clearly wanted to get its side of the story out to a Western audience.
The same was broadly true elsewhere in the region.
When an AP colleague was captured in Afghanistan's civil war in 1993, I traveled to meet one of the country's most notorious warlords, Gulbuddin Hekmatyar, who had seized the reporter, John Jennings, during the course of a battle he was covering.
After a few long days of waiting, I was summoned back to Hekmatyar's compound outside Kabul and Jennings was freed. He had been well-treated and had received care for a shrapnel wound he had suffered at the time of his capture.
Such were the times that even al-Qaida leader Osama bin Laden invited CNN into his lair for a 1997 interview where he explained to an American audience why he had declared a holy war against the U.S.
By this time, the Lebanese hostage-taking a decade earlier appeared to have been a brief aberration. Most Islamist groups, no matter how radical, still preferred to persuade, rather than kidnap journalists.
There was a general sense, valid at the time, that Westerners were unlikely to be snatched because it would be a black mark against any group that took them captive.
"Back then, it did not seem foolhardy to engage Muslim terrorists on the subject of beheading," Jeffrey Goldberg wrote in The Atlantic, referring to time he spent with extremist Pakistani groups in 2000.
The pendulum swung the other way after the attacks of Sept. 11, 2001.
With that seismic event and the wars that followed, Islamic extremism reached new heights and had a direct impact on Westerners working in many Islamic countries. Just a few months later, in January 2002, Wall Street Journal reporter Daniel Pearl was kidnapped in Pakistan and later beheaded on video.
Over the next few years, kidnappings followed by taped executions took place in Iraq, targeting Western journalists, aid workers and contractors. A few lucky captives were released, most of them Europeans for whom ransoms were paid in at least some of the cases.
In 2005, al-Qaida's Ayman al-Zawahiri, then the group's deputy leader and now the top leader, wrote to al-Qaida in Iraq to say they should stop the videotaped beheadings because they would cost the group support among Muslims.
Yet today, the Islamic State, the successor to al-Qaida in Iraq, has made the practice a fundamental part of its battle. Western journalists are enemies to a group that has been hugely successful promoting its own cause on Facebook, YouTube and Twitter.
The most recent issue of the Islamic State magazine, Dabiq, includes an article endorsing the killing of American journalist Steven Sotloff, who was beheaded in September.
"The war against Islam ... is a media war as well as a military and intelligence struggle," the magazine said. "So let the weak-hearted and sick-hearted wake up before defending these 'innocent civilians.' "
Greg Myre, the international editor for NPR.org, covered the Middle East for more than a decade. Follow him @gregmyre1