The editors at Bloomberg make a familiar case against bringing Ukraine into NATO:
Ukraine, a divided and almost bankrupt nation of 45 million, would first have to receive a Membership Action Plan and then meet its conditions — a process that would take many years. (Albania, which joined NATO in 2009, got its MAP in 1999.) So starting the process would merely set the clock ticking for Russia to do whatever it takes to prevent its neighbor from joining — from rekindling the war to eastern Ukraine to making a full-scale invasion.
Next, imagine that Ukraine were, miraculously, to succeed in joining NATO. It would only further destabilize the country. Even though Russia has lately done much to unite most Ukrainians against it, the east of the country still has strong cultural and historical ties to Russia. As long as the Kremlin sees and portrays NATO as a threat, a substantial share of Ukraine’s population will want no part of it. Before the annexation of Crimea, in 2010, 51 percent of Ukrainians opposed joining NATO. (In the east, 72 percent did.) Even today, polls suggest that less than half of Ukrainians want to join the alliance.
The editorial focuses on why NATO membership would be harmful to Ukraine, and I agree with all of this, but I’ll just add a few other observations. Even if the worst-case scenarios described above didn’t happen right away, Ukraine would still be a major liability for the alliance as soon as it was invited. Its future membership would be an ongoing source of tension with Russia that could erupt into another open conflict before Ukraine becomes a full member. The period between being given a MAP and accession would be extremely perilous for the country, since the alliance would not yet be obliged to defend Ukraine while Russia would have every incentive to derail Ukraine’s membership by any means available. There is now no question that Russia will do this, so it would be inexcusable to pursue further NATO expansion as if we don’t know what will happen next.
If Russia reacted so negatively to the prospect of a mere EU association agreement, we can easily imagine how much worse the Russian reaction would be to a MAP for Ukraine. Considering how unwilling members of the alliance are to extend a security guarantee to Ukraine now, it should be obvious that members of the alliance will be similarly unwilling to back up such a guarantee should the need arise in the future. That is why the notion of bringing Ukraine into NATO should be shelved permanently. U.S. relations with Russia and relations between Ukraine and Russia are best served if Ukraine remains a neutral, non-bloc country, and officially confirming Ukraine in that status is the surest available way to reduce the threat from Russia.