World War III or nah? US President Joe Biden and his Russian counterpart Vladimir Putin are set to speak by phone on Tuesday, as the crisis surrounding Ukraine gets dicier by the day. Russia has massed more than 100,000 troops along its border with the country, and the US is warning that Putin is gearing up to invade soon, though the underlying intel isn’t public. No one is quite sure what Putin’s up to with this stunt. Is he trying to pressure Kyiv into moving ahead with the lopsided (but probably best possible) Minsk peace accords of 2015? Or is the Kremlin seeking a broader NATO commitment not to expand further? Or does Putin actually want to invade Ukraine? Either way, Biden has his work cut out for him. Putin is clearly more comfortable risking lives and money to preserve a sphere of influence in Ukraine than the West is, so the US president has to be careful: don’t set out any red lines that NATO isn’t willing to back, but also don’t push the situation into a broader war that no one (ideally) wants.