This post was co-authored with András Simonyi.

President Obama's brief stopover in Tallinn en route to the NATO Summit in Wales this week couldn't have been be any timelier. Showing up in person matters a lot to the Balts who are increasingly feeling the heat after Russia's invasion of Crimea and subsequent aggression in Eastern Ukraine. But besides reaffirming strong U.S. support for the security of its Baltic allies, Obama should also praise Estonia, Latvia and Lithuania for their strong commitment to democracy, human freedom and economic liberalism. Doing so would send an important message to other countries in Central and Eastern Europe who are now struggling to adopt a similar path.

While Putin is tightening his power grip at home in Russia and being increasingly expansionist abroad, unfortunately several Central European allies are now sliding back to a semi-authoritarian system. A very dangerous prospect. Rather than seeking to decouple themselves from Russia, Hungary -- once the champion of democratic reforms and transatlantic integration -- but also Slovakia and even the Czech Republic as well are instead risking becoming more vulnerable to Moscow's economic and political influence. They should know better, given their experience of Russia crushing their hopes for freedom: in Hungary in 1956 and in Czechoslovakia in 1968.

The Baltic states in comparison -- along with Poland -- stand out as a remarkable example of successful post-Communist transition. The three Baltic states all share painful memories of the not-too-distant Soviet occupation, but unlike their Central and Eastern Europe neighbors they are continuing on the necessary albeit sometimes painful path towards democracy and economic liberalism. Underpinning this progress is the Baltic states' steadfast commitment for Euro-Atlantic integration combined with assistance from the U.S. and the Nordic countries.

The result is clearly visible. While Much of Central, Eastern and Southern Europe still struggle with inefficient welfare systems, bureaucracy, economic stagnation, massive debt, rising populism and extremism, political dysfunction and a lack of innovation, the Baltic states are enjoying a stable and efficient political system, strong individual freedoms, low corruption, rising prosperity and innovative economies.

Although they were hit hard by the global financial crisis, their economic recovery has been faster than the European average. All three Baltic states are now projected to soon see steady positive economic growth. Their economies also benefit from being highly integrated with the Nordic countries -- another successful European region.

Estonia is now something of a "European Silicon Valley". Boosted by highly educated, IT-literate and multi-lingual workforce, the country has given birth to an impressive number of IT start-ups -- including the global giant Skype now owned by Microsoft and TransferWise, a global cross-currency money transfer site. Estonia's President has also been a strong champion of "e-governance", which the country is a world leader on.

On foreign policy matters, the Baltic states punch above their weight when it comes to contributing to NATO missions. For a while, Estonia had the highest causality per capita rates during the ISAF operation in Afghanistan. Estonia is also one of the few European NATO allies that spend more than 2 percent of the GDP on defense -- something that the U.S. has strongly encouraged the rest of the alliance to do.

Poland, once the laggard of the region, is pursuing a similar path. A decade ago, the country was still struggling to shake off the remnants of its post-Communist past. Today, its fast-growing economy is the sixth largest in the EU. It has also developed a fully-fledged democratic system, tackled bad governance and corruption, and embraced tolerance and an outward-looking perspective.

During his meeting in Tallinn with the three Baltic leaders, President Obama should offer unwavering U.S. support for their security. This includes supporting the idea that NATO should "preposition" troops and other defense assets in Eastern Europe on a permanent basis. This, together with other efforts already underway, would help serve as a bulwark against potential Russian aggressions. Obama should also pledge to bring U.S.-made Liquefied Natural Gas (LNG) to Europe as a way to boost the continent's energy security from Russia in the short to medium term.

But these efforts alone, however, will not be enough to prevent Russia from continuing to exert its influence on Central and Eastern Europe. As long as the very essence of their societies remains vulnerable, Moscow will try to exploit it. What is needed therefore is a concerted Western effort to strengthen the resilience of Central and Eastern European societies to withstand Moscow's pressure and present a viable alternative to "Putinism". To do this, a heavy dose of democracy, free market liberalism, tolerance and openness should be prescribed. Here, the Baltic countries stand out as a beacon of hope in the midst of turbulent times in Europe.

In Tallinn, President Obama must show passion and commitment to Central and Eastern Europe, and to the transatlantic relationship and the common values it represents. While words are hardly enough to push back on Russian aggression, his statements carry significant symbolic value. He cannot be ambiguous about U.S. support for the Baltic countries.

When Air Force One takes off from the Estonian capital, Vladimir Putin and his admirers should feel a bit less confident about their illiberal ideals.