Ukrainian soldiers guard a road atop their military vehicle near Artemivsk, eastern Ukraine, Monday, Feb. 23, 2015. (Evgeniy Maloletka/AP)

Mikheil Saakashvili, president of Georgia from 2004 to 2013, is chairman of the International Advisory Council on Reforms for the President of Ukraine.

A year ago, events on Kiev’s Maidan square led to the demise of the corrupt, pro-Russian regime of Viktor Yanukovych and to the victory of Ukraine’s pro-European forces. Now Ukraine is engulfed in a nearly full-blown war with Russia and its local proxies. The total area of Ukraine no longer under government control is larger than the size of the Netherlands, and Ukraine’s economy is in free fall while Russia’s stumbles under the weight of Western sanctions. The neighborhood around Russia is in turmoil, and the West seems to be confused and divided about what to do next.

This war is not a land grab, and it is not a war about specific leaders. What is being decided in Ukraine — the largest country in Europe — is whether the post-Soviet space will be allowed to free itself from a vicious cycle of inefficiency, corruption, violence and failed governments to build instead modern, open, democratic societies.

Reforming Ukraine is no simple task. Old habits must be changed. For almost a quarter-century, the preferred occupation of many elites was plundering their own national wealth (often in close cooperation with the Russians), leading to two popular revolutions. But Ukraine’s younger generation is amazing and fearless. It has brought lively debate and an open political system, and finally there is more or less consensus among the political class that business as usual cannot continue. Drastic reform — to tackle corruption, advance deregulation, attract foreign investment and liberate the country from the stranglehold of oligarchs and kleptocrats — is unavoidable.

This month, President Petro Poroshenko invited me to chair an international advisory council to encourage prominent reformers worldwide to help Ukraine succeed in this crucial transition. Foreigners with successful records of reform are also being directly integrated into the government — an unusually bold step, but one that may help Ukraine break the cycle of the past two decades and finally go in a new direction. Police reform — a clear priority after the Maidan demonstrations — has been put under the leadership of Ekaterina Zguladze, who spearheaded an innovative police initiative in Georgia. Another Georgian will direct prosecution reform. Natalie Jaresko, a former U.S. diplomat, has become finance minister. Other foreign nationals have taken key positions in the reform team in Kiev.

These steps will be vital to the defense of Ukraine, which requires three components.

First, and most important, Ukraine must become a successful model of economic growth and democratic reform that is attractive to all Ukrainians — just as West Berlin became a beacon for those in East Berlin and also a symbol to those beyond. For better or worse, Russians feel ties to the land and people of Ukraine. A successful Ukraine will help change Russia for the better by providing the Russian people with a relevant alternative model.

Second, the economic cost for Russian President Vladi­mir Putin must be raised through further economic sanctions, which will eventually help to weaken his position inside Russia, as happened to Serbia’s Slobodan Milosevic in the 1990s.

Third, the military cost for Putin must be raised by supplying Ukraine with defensive weapons, specifically antitank weapons that can halt the further advance of the Russian tanks and armored vehicles. Ukraine may not be a member of NATO, but Ukraine can be encouraged to form bilateral or trilateral regional alliances that can work with NATO and the United States to enhance regional security. And just as the goal of the European Union’s Eastern Partnership program must include full membership for Ukraine in the E.U., full membership in NATO must remain an option if conditions are met.

Both Ukraine and Russia need some tough love from the West. Ukrainian leaders must continue to tackle tough reforms and deliver to their people, and further Western aid packages should be conditioned on these real, deep reforms. But so, too, must Russia pay a price for failing to halt its aggression.

Much more is needed, but failure cannot be an option. The success of Ukrainian reform is the best chance for defending the peace of Europe. The defense of Ukrainian sovereignty will allow Ukraine to become the European nation that Ukrainians have twice taken to the streets to demand — the nation, and the ideals, they now shed blood for in the east.

One thing is clear: The post-Cold War order in Europe has been irreversibly undermined. New solutions need to be found to avoid further chaos. But the West should accept that Putin is not just after pieces of the former Soviet empire. He clearly regards his hybrid war as payback for Russia’s defeat in the Cold War. Ukraine is Putin’s frontline in a standoff with the West. It is his West Berlin — the taking of which was a matter of principle for Stalin and the successful protection of which ultimately reversed the spread of communism in Europe. The dismantlement of Ukraine is how Putin seeks to erode the values of the transatlantic alliance, and the future of Europe is no less at risk than it was decades ago in Germany.

The West must also accept that Ukraine is today’s West Berlin: the frontline in the defense of Western values against Russian revanchism.