Do not mess with Nato members - that is the message for Russia that US President Barack Obama intends to convey as he visits the Baltics on the eve of a critical summit of Western alliance members.
His visit comes at a time of high tension in Europe, with the United States-led alliance accusing Russian President Vladimir Putin of sending troops, tanks and other weapons to battle in Ukraine in support of those who seek to take chunks out of the country to form a "new Russia".
In a blunt message to Moscow before Mr Obama left for Europe, Mr Charles Kupchan, who manages European affairs in the White House, said at a press briefing: "Don't even think about messing around in Estonia or in any of the Baltic areas in the same way that you have been messing around in Ukraine."
The US commitment to Nato's pledge of collective defence is particularly important for the three small and vulnerable Baltic states of Estonia, Latvia and Lithuania. Current members of Nato, they were once part of the Soviet Union and are now rattled by an increasingly assertive Moscow in the neighbourhood.
But Mr Obama will need to do more than just deliver speeches to deter Russia. For, as things stand, Mr Putin retains the upper hand in the region.
The Baltic nations have good reasons to fear Moscow's intentions. All three gained their independence from Russia at the end of World War I, lost it two decades later in World War II, when they were forcibly re-incorporated in the Soviet Union, and regained their freedoms only in 1991 when the USSR disintegrated.
The people of the Baltics thus see the crisis in Ukraine as a rerun of history. There is another chilling parallel - just as in Ukraine, some Baltic states contain large numbers of ethnic Russians who could be encouraged by Moscow to undermine the independence and territorial integrity of the countries in which they reside.
About one million ethnic Russians live in the Baltic region, accounting for a quarter of the population in both Estonia and Latvia.
Unlike Ukraine, the Baltic states are among Europe's most prosperous nations. But they are so small as to be defenceless against Russia: Between them, the three nations number a mere 6.2 million inhabitants.
And, as Baltic leaders point out, what is happening in Ukraine challenges all their continent's security arrangements. "Practically, Russia is in a state of war against Europe," says Lithuanian President Dalia Grybauskaite.
Mr Obama's visit will go some way towards addressing these jitters. He will hold a symbolic joint meeting with the leaders of the three countries. And, in a speech in the Estonian capital later today, he will remind his audience that the American guarantee to defend them is not just a political undertaking but a legally binding obligation enshrined in the Nato treaty.
"We will let the Estonians know that we mean what we say with respect to our treaty obligations," Mr Obama said on the eve of his departure to the region.
The snag is that in order to render such treaty obligations credible, Nato has to station troops on Baltic soil.
Without them, the Russian military, which has sizeable numbers of battle-ready forces in the region, is capable of mounting a surprise attack which will overrun the Baltic states within hours, well before Nato can even consult its member states about a response.
Western military planners acknowledge the problem. "Speed is of the essence to deter sudden threats along Nato's borders," says US Air Force General Philip Breedlove, who commands all allied forces.
But Mr Obama and many other Nato leaders have ruled out, at least for now, the establishment of new permanent military bases in the Baltics, which is both expensive and likely to antagonise Russia.
Instead, what Mr Obama will be offering them is an expanded list of Nato training exercises, new deliveries of weapons, a rapid deployment force for crises and plans to rotate more Nato troops through the region.
Baltic leaders have no choice but to embrace the offer, limited though it is. Last week, Nato jets had to be scrambled several times to intercept Russian bombers and fighters approaching Baltic airspace in menacing formations. Latvia has also spotted Russian submarines just outside its territorial waters. The message from Mr Putin is clear: Once the US presidential plane departs from Estonia, Russia will still be there, looming over the region.
This article was first published on September 03, 2014.
Get a copy of The Straits Times or go to straitstimes.com for more stories.