People stand, on July 17, 2014, amongst the wreckages of the Malaysian airliner carrying 295 people from Amsterdam to Kuala Lumpur after it crashed, near the town of Shaktarsk, in rebel-held east Ukraine. Pro-Russian rebels fighting central Kiev authorities claimed on Thursday that the Malaysian airline that crashed in Ukraine had been shot down by a Ukrainian jet. The head of Ukraine’s air traffic control agency said Thursday that the crew of the Malaysia Airlines jet that crashed in the separatist east had reported no problems during flight. (DOMINIQUE FAGET/AFP/Getty Images)

This is a hotline moment: When a civilian passenger plane is shot down over a war zone, leaders are forced to see — and hopefully, discuss — the unintended consequences of battle and the accidental risk of war. But, paradoxically, horrifying moments like this can also encourage government leaders to break from the status quo and its cycle of escalation — and think about ways to move back from the brink.

The caveats, first: At this writing, all we know for sure is that Malaysia Airlines Flight MH17 crashed Thursday in eastern Ukraine, killing all 298 passengers and crew members. The plane was near the border-area battleground between Ukraine’s military and pro-Russian separatists. The Ukrainian rebels have received heavy weapons from Russia, reportedly including anti-aircraft missiles that might be able to reach the 33,000-foot altitude at which the plane reportedly was flying.

For now, it’s a retaliatory war of words: Ukraine’s President Petro Poroshenko called it “a terrorist act,” with the implication that the Russian-backed separatists were to blame. Andrei Purgin, a leader of the breakaway “Donetsk People’s Republic” in eastern Ukraine, denied that the insurgents were responsible or that they had missiles that could have downed the plane.

This nightmare incident could have a perverse benefit, if it leads Russia to reconsider the consequences of its reckless campaign in Ukraine. The incident illustrates how a confrontation can escalate beyond what any side intends or desires. We mark such a mistake next month, with the hundredth anniversary of World War I, when European powers went to war through a series of lockstep mobilizations that led to a ruinously bloody war from which Europe and Russia arguably have never recovered. Nobody intended that outcome, but nobody could stop it, either.

Recent history offers two examples in which inadvertent attacks on civilian airliners demonstrated the risks of military confrontation but also led, over time, to a process of sober reflection and eventual de-escalation.

The first such incident was the Sept. 1, 1983 attack that downed Korean Air Lines Flight 007 near Sakahlin Island, a missile testing zone on the far eastern coast of what was then the Soviet Union. The plane was brought down by a Soviet fighter jets, but Moscow initially denied responsibility and then claimed the passenger jet had been on a spy mission. In truth, it was a hideous accident in the fog of the Cold War that illustrated how Moscow and Washington were operating on a hair trigger. The vituperative reaction in Washington led some Soviets to fear that all-out war might be ahead — and this, in turn, contributed to a period of reflection that eventually led both sides to consider new arms control agreements and other measures of détente. Indeed, viewed through history’s lens, you can discern a connection between the KAL shootdown and the eventual end of the Cold War and collapse of the Soviet Union.

Disasters sometimes create political space and allow leaders to take actions that previously were unthinkable. That was the case with another fatal accidental attack on a civilian airliner — in this case the July 3, 1988 downing of Iran Air Flight 655 by the U.S.S. Vincennes. The Navy guided-missile cruiser was stationed in the Persian Gulf protecting oil tankers during the eighth year of the Iraq-Iran war. The attack, the result of misidentification according to the U.S., resulted in the death of 290 passengers and crew. Iran said at the time it believed the attack was deliberate on the part of the United States. That was almost certainly wrong, but it lead Iran’s Supreme Leader, Ayatollah Khomeini, to conclude that the war with Iraq was unwinnable and to sue for peace. As he put it, Khomeini “drank from the poisoned chalice” and agreed to negotiate an end to the war. Here, again, you can draw a line from a disastrous mistake in battle to an eventual settlement of conflict.

Nobody knows if the tragic events over eastern Ukraine will lead to wise reflection in Moscow and a move toward de-escalation, or whether tensions will exacerbate even further. Sometimes, disaster makes people stop and think; other times, it just leads to worse disaster. But certainly the loss of the Malaysia Airlines jet should encourage European nations, such as Germany, that sanctions against Russia that push it toward peace are preferable to letting the haphazard process of tit-for-tat continue.