U.S. President Barack Obama spent the past four days in Europe visiting his two oldest and closest foreign political allies, spending considerable political capital on issues close to their hearts.

The time and energy put into the visits to London and Germany — likely the last of his presidency — signaled Obama's affection and trust for two leaders who have stood with him through his toughest economic and foreign policy decisions.

But the trip also highlighted Obama's concerns about the shaky global economy and the ripple effects of the conflict in Syria — priorities he wants to work on before his term ends next Jan. 20.