A local man looks at the craters from the shells at the central street of Debaltsevo, Donetsk area, Ukraine, 20 January 2015. (Anastasia Vlasova/EPA)

EUROPEAN FOREIGN ministers met Monday to consider proposals for resuming diplomatic contacts and cooperation with Russia in a range of areas — a strategy pressed by several governments that wish to paper over the breach opened by Moscow’s invasion of Ukraine. Unfortunately for the doves, the discussion came just as Russian forces, after several weeks of relative calm, launched a new offensive in eastern Ukraine.

By Tuesday, the Ukrainian government and the U.S. ambassador to Ukraine were reporting that fresh Russian army units were crossing the border and attacking Ukrainian positions north of the city of Luhansk and at the Donetsk airport. “The situation,” European Union foreign policy chief Federica Mogherini told us shortly after arriving in Washington, “is not going in the right direction.” Appropriately, the European ministers concluded there were no grounds for altering the existing sanctions on Russia, some of which will come up for renewal at a summit meeting in March — and the plan for detente came under heavy criticism.

The episode illustrates a pervasive disconnect in Western thinking about the regime of Vladi­mir Putin. As Kadri Liik of the European Council on Foreign Relations pointed out recently , many Western leaders persist in seeing the Ukraine invasion as a hiccup in relations with Russia that can be smoothed over, rather than as a demonstration that Mr. Putin’s agenda is fundamentally at odds with Europe’s security interests and its values. Because of their attachment to the hiccup theory, governments — including the Obama administration — have refused to take steps, such as providing the Ukrainian government with defensive weapons, that could help stop Mr. Putin’s aggression. Instead, they concoct futile schemes for “reengaging” the Russian ruler.

Ms. Mogherini, a former Italian foreign minister often described as a leading advocate of this soft line, told us that she did not foresee “a return to business as usual” with Moscow. She stressed that European ministers were committed to the principle that any alteration of sanctions must be linked to Russia’s full implementation of the Minsk agreement, an accord signed in September that requires the removal of Russian forces from Ukraine and international monitoring of the border. Meeting those terms would require an unprecedented reversal from Mr. Putin, who has never allowed a Russian retreat from occupied territories in Eurasia.

Nevertheless, the renewed fighting in eastern Ukraine underlines the reality that the European Union and the Obama administration need a more coherent strategy for answering Mr. Putin’s actual — as opposed to wished-for — behavior. While sanctions have had an impact on the Russian economy, they clearly have not deterred Mr. Putin from continuing the war. As a start, there must be a stronger commitment to the government in Kiev, which is in worse shape than the Russian regime. Struggling to hold the military line, it may soon be forced to default on its foreign debts because of a lack of Western support. So far, U.S. and E.U. pledges for this year amount to $4 billion against a $15 billion funding gap.

Rather than debating when they can resume trade discussions with Moscow, Western leaders should be deciding whether they are willing to do what will be necessary to preserve Ukraine’s independence.