Kurt Volker and Erik Brattberg may consider it a mere detail that Ukraine isn’t a NATO member, but that fact provides the alliance with the strongest of reasons for avoiding an unnecessary confrontation [“NATO must not flinch from Putin,” Washington Forum, Aug. 29]. The appropriate response of NATO to Russian President Vladimir Putin’s adventurism is to reaffirm the mutual-defense commitments of its members and, if necessary, bolster alliance forces in NATO countries on the periphery of Russia.

Mr. Putin may interpret such actions as giving tacit consent to Ukraine’s partition. But the self-imagined strongman is walking into a trap of his own setting: The Russian people won’t sacrifice their sons to a Slavic civil war.

Stephen Munro, Silver Spring

How many Post articles have been written recently about Russian President Vladimir Putin’s aggression in Ukraine and what to do about it?

So far nothing has deterred Mr. Putin, certainly not the Obama administration’s so-called sanctions, while our European allies have not done anything to disrupt their relationship with Russia [“Mr. Putin’s invasion,” editorial, Aug. 29].

Consider that energy basically drives the Russian economy, and Europe is the country’s biggest customer. Our European friends have let themselves become beholden to natural gas from Russia.

Suppose President Obama did something totally out of character, such as taking on a bold initiative to provide natural gas to Europe. We have a plentiful supply and, with a commitment from our allies, liquefied natural gas tankers could be built and within a couple years supplies of natural gas could be delivered to Europe. Mr. Putin then would understand the impact such a move would have on his economy, and that would quickly bring him to the negotiating table and bring about his exit from Ukraine.

Bob Jeffress, Potomac Falls