Ukraine is deteriorating, and quickly. The brief honeymoon that followed Petro Poroshenko’s inauguration as president is over. It is time for the West to step up its actions.

The past few days have seen a dangerous escalation of the crisis. On June 14, pro-Russian fighters shot down a Ukrainian military transport jet as it was trying to land at Luhansk airport in Eastern Ukraine. The Ukrainian prosecutor’s office said all 49 people on board—40 paratroopers and nine crew members—had died.

NATO provided satellite imagery showing Russian tanks and heavy artillery crossing the border into Ukraine. The deliveries, shown in three sets of images dated May 30, June 6, and June 11, also included rocket launchers, according to the U.S. State Department.

Angela Merkel, the German chancellor, and François Hollande, the French president, spoke to Russian President Vladimir Putin on June 14 asking him to control better Russia’s borders with Ukraine. But so far, every one of Merkel’s attempts to persuade Putin to stop Russia’s support for militia groups in Eastern Ukraine has failed.

Russia continues to deny it is arming rebels in the East of Ukraine. Instead, Putin has called on the Ukrainian government to stop its military operations. Yet Kiev is simply attempting to regain control of its territory while also trying to establish some dialogue with Moscow to end the crisis.

In this situation, doing nothing is not an option for Europe or America. The longer European governments hesitate, the more Ukraine is threatened by civil war. Its citizens will flee the conflict, and the growing humanitarian crisis in the East of the country will increase.

There may also be spillover into other parts of Eastern Europe. Just consider the political instability in Moldova and Russia’s meddling in Transnistria, not to speak of the lingering conflict between Armenia and Azerbaijan over the territory of Nagorno-Karabakh.

European leaders cannot afford to believe that the Ukraine crisis will just fade away. It won’t. Nor will they be able to contain it unless they act. Given Russia’s continued meddling, Merkel needs to push the EU to impose a third round of sanctions.

It is true that the first two rounds of sanctions have had only an indirect impact on the Russian economy, while Putin’s popularity continues at an all-time high. But that should not deter the EU and the United States from pressing ahead with targeted sanctions that would include a visa ban for Putin’s inner circle combined with the freezing of their assets and a comprehensive ban on arms exports.

NATO can’t stand idly by, either. The measures U.S. President Barack Obama announced in Warsaw on June 5 go some way toward reassuring NATO’s Eastern allies. Yes, it is important that NATO conducts training and sends troops on a rotational basis to Poland, the Baltic states, and Romania. But is that really enough to deter Russia? Poland and Estonia both want permanent NATO bases on their territories. Such a presence could have an immense psychological impact for the region—and for Russia.

There are other tough decisions that NATO will have to make at its summit in South Wales in September. Georgia wants to be granted a NATO Membership Action Plan, a program of advice and practical support that would set the country on an unambiguous path toward membership.

Several European countries oppose giving the Membership Action Plan to Georgia, not only because they argue it would provoke Russia but also because they doubt that NATO would be prepared to defend Georgia in case of an armed conflict. So what takes precedence: meeting NATO’s criteria, or pandering to Russia?

NATO and the EU also have to decide how to deal with Moldova. Together with Georgia, Moldova wants to sign a political and economic association agreement with the EU. Russia is keen to stop that from happening. The reason isn’t just that Chişinău, despite all its systemic weaknesses, and Tbilisi would move economically closer to Europe. The impact these accords would have on strengthening civil society and democratic values cannot be underestimated, as the Kremlin now understands, and fears.

That is why the Kremlin has also embarked on an anti-EU and anti-NATO campaign further afield, in Montenegro, a small Western Balkan country that wants to join both Western organizations. Despite a pervasive culture of corruption, Prime Minister Milo Đukanović is hoping that Montenegro will become the 29th member of NATO at the alliance’s September summit.

Don’t bet on it. Montenegro is vulnerable to pressure from Moscow. Russians own about 40 percent of the republic’s Adriatic coast. Up to 7,000 permanent Russian residents have taken advantage of the country’s lax rule of law, while Russian businesses have heavily invested in the republic, not always to Montenegro’s advantage.

It is precisely to break this Russian stranglehold that part of the Montenegrin political class now wants to wed the country to the Euro-Atlantic organizations. But analysts in the region say that Russian propaganda in the Western Balkans has been stepped up over the past year to prevent that from happening.

In this situation, Western governments need to understand that their neighborhood is being drawn into Moscow’s power games and the Ukraine crisis. That is why further sanctions against Putin, the establishment of permanent bases in Eastern European NATO countries, and unstinting support for civil society and democratic institutions throughout Eastern Europe is crucial. The competition about values has only begun.