It appears that the US, possibly with NATO allies, may soon embark on providing arms to Ukraine to help Kiev counter Russian and separatist aggression in the east. The reasons for assisting President Petro Poroshenko’s government are self-evident. Following the Maidan Square protests last year that evicted the corrupt President Viktor Yanukovych from office, Vladimir Putin was determined to maintain Russian influence and control over its former ally. Shortly thereafter, Russia annexed Crimea and physically intervened in the east with so-called “green men” wearing insignia-less military uniforms arming and supporting the anti-Kiev separatists. Civil war and conflict have continued since. While Poroshenko has begun vitally needed reforms of an otherwise corrupt government, Ukraine’s dire economic and financial conditions require billions of Euros in aid and loans simply to survive. Meanwhile, Putin is threatening the city of Mariupol on the Sea of Azov and is clearly considering turning eastern Ukraine into a vassal state. While Ukraine is neither a member of NATO or the EU, Putin’s actions have generated fears in and concerted action by the west on the grounds that the post-Cold War order in which national boundaries were inviolable would no longer be respected by Moscow. The smaller Baltic and southern tier states of Europe felt particularly vulnerable to Russian intimidation and so-called ‘hybrid’ warfare including offensive use of cyber. Sanctions that have hurt Russia’s economy have been imposed. NATO has responded with troop deployments to the flanks, a readiness action plan, new exercises and reaffirmation of Article Five guarantees pledging an attack against one is an attack against all. Now, equipping Ukraine with military arms is being argued as vital to countering Putin’s continuing aggressing. The logic is clear. However, the larger question of whether such steps will ameliorate or exacerbate the civil war must be more closely examined. Russia has a vote in this. And long-term consequences, likewise, will count. The successful arming of Afghan mujahideen with Stinger missiles surely led to the defeat of Soviet forces a quarter of a century ago in Afghanistan. Yet, from that victory arose the Taliban and Afghanistan still is far from stable or safe. Three questions should guide western decisions. First, why has President Barack Obama not yet challenged Putin to state Russian intentions and aims in Ukraine? ‘Off-ramps’ and negotiations as well as ample explanation of the impact of sanctions on Russia have been offered. Yet Putin must be confronted with explaining what he sees as an acceptable outcome. Second, how far are NATO and its membership prepared to push the limits of Article Five? No one in the alliance is prepared to go to war over keeping Ukraine independent or at least accepting that responsibility. However, as Putin has aggressively used Russian bombers over international airspace with turned off transponders to threaten civilian air travel, will he attempt further intimidation and possibly hybrid tactics against the most exposed of the NATO states on the flanks most adjacent to Russia? In those circumstances, how far will NATO go in responding? Last, the one area in which Moscow maintains an order of magnitude (i.e. at least 10-fold) numerical military advantage over NATO is in possession of theatre or short range, tactical nuclear weapons. Nuclear muscle flexing is not beyond Putin’s imagination. And one can imagine, under certain circumstances and indeed with a newly announced military doctrine, that Putin could infer to or indeed threaten potential use of nuclear weapons in response to what Moscow might propagandise as provocative NATO actions. In an ideal world, giving Kiev more than equal footing in militarily defeating the separatists would seem unarguable. Of course, such equipping would take time and would risk escalating the fighting and destruction irrespective of Putin’s reactions. Sadly, this is not an ideal world. Covert action in providing arms might have been preferable. At least the cover of plausible deniability was attractive. However, that time, if it ever were present, is long past. Hence, if Ukraine is to be armed, the west must announce a new doctrine that lays out the rationale as well as the path towards political negotiations to end this crisis. Putin is indeed the wild card. And, in that regard, it is not unfair to remind ourselves of what happened half a year more than a century ago at Sarajevo. No one wanted a world war then. No one wants a major conflict over Ukraine, at least in the west. So Mr Putin, what is your view? The world needs to know and know now. The writer is chairman of the Killowen Group that advises leaders of government and business and senior advisor at Washington DC’s Atlantic Council. His latest book, due out this fall, is A Handful of Bullets: How the Murder of an Archduke a Century Ago Still Menaces Peace Today