Four days on from the downing of the plane, both scenarios remain possible.
An assessment of the strategies and pressures in play in the conflict that has killed more than 400 people aside from the victims of the crash:
The Boeing 777 was almost certainly shot down, but who did it remains hotly disputed. Ukrainian authorities and Western countries mostly blame pro-Russia separatists in eastern Ukraine and there are some suggestions that Russia itself may have fired the missile. Russia, which denies allegations it is directing or aiding the rebels, hasn't directly lain the blame on anyone but its statements imply that Ukrainian forces were responsible.
Few think a definitive conclusion, if one can be reached, will be possible imminently. Despite calls for a full-scale international investigation, a probe has yet to begin and even when one begins, investigators will face a severely compromised crash scene. Rebels who control the crash site have allegedly interfered with the crash site by spiriting away bodies and hauled off pieces of evidence; the status of the plane's "black box" data and voice recorders remains unclear.
Given the huge opprobrium that would fall on whichever side brought down the plane, any report assigning fault would likely be vociferously disputed or rejected by the nominally guilty party.
A cease-fire in the wake of the crash has also yet to be observed despite calls from all around the world, including by Russia. The prospects of one emerging appear slim if history is any guide — in late June, a cease-fire called by the Ukrainian government side barely got off the ground.
The anger on the government side is also so high that any move toward compromise would likely be seen as a meek submission to violent and heedless forces already routinely characterized as "terrorists."
The rebels, meanwhile, dismissed the June cease-fire as a ruse by the Ukrainian army to reinforce positions and equipment in the east. That suspicion persists in the wake of a run of successes by the Ukrainian army.
Even if a cease-fire was called and crucially held, a comprehensive settlement would require peace talks. But the deep-rooted issues that set off the conflict remain. By signing an association agreement with the European Union, Ukraine has signaled it is determined to move out of Moscow's orbit — the issue that set off the crisis last November. Earlier vague proposals of mollifying the east by giving the regions more autonomy may have passed the test of time — rebels who declared the Donetsk and Luhansk regions independent may not be able to stomach remaining part of Ukraine even with enhanced local power.
Although Russian officials have publicly dismissed Western sanctions imposed on those alleged to be supporting or directing the rebels, the measures are having enough effect that Moscow is leery of provoking more. Despite vowing to defend ethnic Russians in any country, Russian President Vladimir Putin has held back from openly intervening in Ukraine. He has even shown superficial interest in de-escalating the conflict by urging the rebels to recognize Ukraine's presidential election in May. Putin has also asked the Russian parliament to cancel its resolution allowing the use of Russian forces in Ukraine.
However, Putin may view a frozen conflict as an opportunity to keep Ukraine in a limbo that would block any efforts by Kiev to move closer to NATO. It could also discourage the foreign investment that Ukraine badly needs.
On the ground
After a confused start to its offensive against the rebels, the Ukrainian military has taken back about half of the territory once held by the rebels. But the region's two main cities, Donetsk and Luhansk, remain in the hands of the rebels and Ukraine's forces may face many impediments in taking them back. Their main strategy has been to blockade the cities, not to shell them. But blockades can starve the cities, whose combined population was about 1.5 million at the start of the hostilities, or provoke a huge wave of displaced people that Ukraine is ill-equipped to handle. If the Ukrainian armed forces turn to force, then the ensuing urban warfare could favor the guerrillas.
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