Putin’s talk with Trump was free of any lecture, as the Kremlin was keen to emphasise. It centered on combatting international terrorism as the shared agenda for a future US-Russia partnership. The Kremlin has welcomed the sharp shift by the Trump administration to prioritize “radical Islamic terrorism” as the principal national security threat to the United States, delegating Russia to second or even third-tier priority.

Trump’s conversation with Putin was noticeably warmer that his phone encounters the same day with German Chancellor Angela Merkel and French President Francois Hollande. Both had to remind Trump of the fundamental importance of the NATO alliance in transatlantic security, the existing benchmarks for lifting Russia sanctions (Russia’s implementing the Minsk agreements) and the need to uphold the nuclear agreement with Iran. Merkel even had to lecture Trump on U.S. obligations under the Geneva conventions to accept refugees fleeing war.

Russian President Vladimir Putin and U.S. President Donald Trump had their first phone chat over the weekend. By all accounts it was amiable, and may move the US-Russia relationship from its state of deep-freeze imposed during the final months of the Obama administration.

Hours before the call with Putin, Trump signed an Executive Order calling for a new ISIS strategy that specifically authorizes the Pentagon to look for new coalition partners. In a related move, the new president reorganized his National Security Council in a way that lessened the influence of those players who consider Russia to be an existential threat. His changes removed the chairman of the Joint Chiefs of Staff and the Director of National Intelligence from the Principals Committee, and elevated the role of Chief Strategist Steve Bannon. Together with National Security Advisor Michael Flynn, Bannon has made the case for engagement with Russia to defeat ISIS.

All of this fits neatly with the Kremlin’s objectives to end international isolation over Ukraine, and to re-position Russia as a peer player. Trump’s focus on defeating ISIS fulfills Moscow’s aspiration for a U.S.- and Russia-led international coalition against terror, as proposed by Putin in his UN General Assembly address in September 2015.

With its deployed assets in Syria and elsewhere in the Middle East, Russia is uniquely positioned to become America’s principal partner in the war on ISIS. With the exception of Turkey, which is suspicious of the Pentagon’s alliance with the Kurdish forces, no other country is in an immediate position to bring more force to bear on ISIS strongholds in Syria and Iraq. It is quite likely that U.S.-Russia cooperation to defeat ISIS will also extend to Libya. The Trump administration may eventually embrace Russia’s strategy of backing the Libyan National Army of General Khalifa Haftar, supported by key U.S. regional allies like Egypt, UAE, and Saudi Arabia.

In this brave new world, Russia could be more important to Washington as a war ally, and Europe and NATO will have to compete against Russia for Washington’s attention. This could reshape the nature of the Atlantic alliance, shifting its focus from deterring Russia to fighting global threats, making NATO “less obsolete”. This new world would be a one where Russia and the United States would have primacy over other states in Europe. The same would apply to the U.S. alliances in Asia, where countries like Japan would have to look to Russia for supplemental reassurance against Chinese dominance.

The emphasis on a new strategic partnership to defeat ISIS also allows Moscow and Washington to conveniently sidestep the tricky question of U.S. sanctions relief. Trump promised to put this on the table, but, in truth, sanctions currently are not a life or death issue for Moscow. It can live with a vague promise to “normalize economic and trade relations.” For Trump, the silence on sanctions makes a legislative effort in Congress to impose them by law less likely. Meanwhile, achieving a meaningful alliance against ISIS with Russia might clear the air for lifting sanctions down the road.

The key question is whether sanctions relief will be decoupled from the implementation of the Minsk peace agreements for Ukraine. Both Merkel and Hollande have urged Trump not to do this. If the Trump administration were to lift the eastern Ukrainian sanctions unilaterally, it would essentially free Kiev from its obligations under the Minsk agreements, and leave Russia to effectively own the Donbass. Moscow would probably reassure Washington that this would not trigger a new war in Ukraine. It would seek, and likely get, Trump’s acquiescence to Russia’s meddling in Ukrainian politics to install a Russia-friendly government in Kiev.

The Trump administration would also seek to leverage its new bromance with Moscow for Russia’s cooperation in containing Iran and China.

Moscow might be happy to milk Washington with regard to Iran, where the relationship is of rivalry and distrust, but it would hate being dragged into a conflict with China. It would not take any positions that might be construed as siding with Washington against China, be it on trade or security, although it would welcome the opportunity to leverage better ties with the U.S. for a more balanced Russian-Chinese relationship. The way to do this might not be security ties, but economic cooperation between Russia and the United States in Russia’s Far East, modelled on the new Russia-Japan partnership.

This delicate balancing act requires some sophisticated diplomacy and a significant level of trust.

Whether this is achievable remains an open question.