With more than 3,500 people killed in ongoing fighting between pro-Russian separatists and Ukrainian troops, it is perhaps fitting that the position in Kyiv with the least job security appears to be post of defense minister.
President Petro Poroshenko nominated National Guard commander Stepan Poltorak as his new defense minister on October 13, one day after accepting the resignation of Valeriy Heletey, who had served in the position for just three months.
Like Heletey, who was forced to step down following outrage over heavy casualties suffered by Ukrainian troops during an ambush in Ilovaysk, all three of Poltorak's predecessors have struggled to get a handle on Moscow's interventions on Ukraine's Russian-speaking regions.
Ihor Tenyukh: From Euromaidan Revolution To Crimea Annexation
A former naval commander and a member of the far-right Svoboda party, Tenyukh joined Ukraine's "kamikaze cabinet" as acting defense minister in February, in the heady days that followed the two-month Euromaidan revolution that ousted pro-Moscow President Viktor Yanukovych.
He gained popularity during the Euromaidan demonstrations, where he warned military personnel to resist any potential "illegal" orders to suppress protesters.
But during his one-month tenure, Russian troops invaded Crimea and Moscow annexed the territory. Ukrainian soldiers on the peninsula, apparently stuck in limbo, spoke of a lack of direction coming from Kyiv and both parliament deputies and protesters accused Tenyukh of costly indecisiveness.
Following a speech in which he said he would "not cling to my post," the Verkhovna Rada voted to accept his resignation on March 25.
Mykhaylo Koval: From Indecision In The East To War In Donbas
Just weeks after Russia annexed Crimea, armed pro-Russian separatists began occupying state administration buildings in the eastern regions of Donetsk and Luhansk.
Kyiv's initial response appeared confused, with clearly unprepared soldiers in tanks forced to face off with unarmed pro-Russian civilians who formed a corridor around the militants' positions.
With fears that Russia would attempt to repeat the "Crimea scenario" in Ukraine's east appearing to become a reality and with many suspecting the army would be unable to fend off the challenge on its own, armed battalions, nominally run under the auspices of the Interior Ministry, began to take shape.
Newly appointed Defense Minister Valeriy Heletey (right) and former acting Defense Minister Mykhaylo Koval (left) talk in front of Defense Ministry headquarters in Kyiv July 3.
Fighting intensified just after Petro Poroshenko was elected president in late May. And after a failed cease-fire in June, the new Ukrainian president resolved to launch a full-scale military campaign to win back the east with his own team in place. On July 3, he replaced Koval with Valeriy Heletey, who was previously in charge of presidential and parliamentary security.
Valeriy Heletey: Some Military Gains, A 'Massacre,' And A 'Cease-Fire'
Heletey set the bar high for himself at the outset. "Believe me, there will be a victory parade" in Crimea," he told lawmakers after being confirmed by parliament.
Throughout July and most of August, Kyiv's aggressive campaign appeared to put fighters from the self-proclaimed Donetsk and Luhansk republics on the defensive and by mid-August pro-Ukraine forces had the major holdout cities of Luhansk and Donetsk nearly surrounded.
But with the help of what is widely believed to have been thousands of Russian troops, the separatists in late August managed to open up a new front along the Azov Sea from the border with Russia and close to the crucial port city of Mariupol.
And in a crushing blow to public confidence in Ukraine's armed forces, the military failed to protect National Guard troops surrounded by pro-Russian units in Ilovaysk, east of Donetsk. Over 100 troops died during a surprise attack and others were taken prisoner.
According to the editor in chief of the LB.ua news website, whose colleague was embedded with pro-Kyiv fighters in Ilovaysk, Heletey was so unprepared for the events there that he texted to ask her for the coordinates of Russian troop movements.
A cease-fire negotiated between Poroshenko and Russian President Vladimir Putin in early September has slowed the violence slightly, but intense fighting around Donetsk's airport has continued and according to the United Nations, at least 331 people have died since.
Stepan Poltorak: A Safer Choice?
Poroshenko is set to meet Putin again this week and Moscow has announced that troops on the border will be sent back to their bases.
The new defense minister will likely be tasked with maintaining the territorial status quo -- with Ukraine at least temporarily accepting the existence of a breakaway outpost while trying to prevent it from spreading further.
The appointment of Poltorak appears to be a recognition of the importance of the battalions making up Ukraine's National Guard -- who have served in the front lines in key battles.
Popular among Ukraine's armed forces, and having accomplished the task of creating the volunteer National Guard after Crimea's annexation, the hope may be that his experience over the past six months in this new kind of war is what a new Ukrainian military leadership needs.
At least that's Poroshenko's hope. "I talked to the generals and met regular soldiers, battalion commanders," he said. "These conversations convinced me about the accuracy of my choice."