Several hours after issuing an unprecedented statement against President Trump's threats to take over Greenland, the leaders of France, Germany and the U.K. stood side by side with Trump's top advisers in Paris and announced joint security guarantees for Ukraine. Why it matters: The events of the last few days — in particular, Trump's renewed threats on Greenland in the aftermath of the Venezuela raid — left real doubts in Europe about whether the transatlantic alliance still exists. A senior Trump adviser acknowledged there's deep concern in Europe about Greenland but stressed the administration's plans and discussions on this issue are in the very early stages.