Proponents of improved U.S.-Russian relations might take heart in Donald Trump’s surprise victory in the U.S. presidential election. Tangible positive changes are certainly possible, but fundamental differences over issues such as U.S. missile defense, NATO expansion and Russia’s willingness to use force against its neighbors, as well as the absence of robust economic ties, make a qualitative breakthrough in the bilateral relationship unlikely.

To hear Vladimir Putin say it, Russia is not at war with Ukraine. “I think that this apocalyptic scenario is highly unlikely, and I hope it never comes to that,” Putin said when asked on Russia’s Defender of the Fatherland Day whether his fellow citizens may “wake up one day to learn we are at war” with Ukraine. It can be inferred that the commander-in-chief of the Russian armed force believes (or wants us to believe) that there will be no war between Russia and Ukraine for as long as Moscow refuses to admit to its involvement in the conflict. But is there such a thing as a declared war any more? And how should other European nations respond if they become the target of an undeclared war? What can be done to prevent repetition of the Ukraine scenario elsewhere in Europe?

The last several days have seen the once dormant debate—whether or not the U.S. should start supplying weapons to Ukraine—reignite.  The debate was revived by the release of a joint report by a group of ex-U.S. officials affiliated with three prominent American think tanks, which recommended that Washington urgently supply anti-tank missiles, counter-battery radars, and other military hardware to the Ukrainian armed forces so that the latter can deter Russia from escalating the conflict in Donbass.

It is indisputable that the Ukraine crisis has dealt a serious blow to Russia's relations with core members of NATO. It would take many years for Moscow, Washington and Brussels to fully mend the fences even if the conflict in Ukraine were resolved tomorrow.

But as Russia's new military doctrine indicates, the Rubicon in NATO-Russian relations has not been crossed — at least not yet. While naming Russia's allies, the doctrine, which was published on Dec. 26, avoids designating either NATO as a whole or any of its specific members as adversaries.

As the triumphant soldiers of Ukraine’s protest movement savor their victory on the streets and squares of Kiev, their commanders probably can’t help wondering how the Kremlin will respond to the ouster of Ukraine’s ‘pro-Russian’ president Viktor Yanukovych. Vladimir Putin has condemned the forceful seizure of power in Ukraine and suspended promised purchase of Ukrainian bonds. But the question remains: will Russia’s strongman get actively involved in the chaos of Ukrainian politics as he did back during the previous Ukrainian evolution when he rallied for Yanukovych?