The year 2015 closed with hope. International representatives defied the naysayers and concluded an agreement that could lay the foundation for an effective response to climate change. India's Prime Minister Narendra Modi made a surprise stop in Pakistan on the way home from Afghanistan, meeting his counterpart, Prime Minister Nawaz Sharif, to boost long-stalled peace talks between the two nuclear-armed neighbors. In Iraq, the beleaguered army won an important victory by retaking the city of Ramadi, lost seven months ago to Islamic State militants.

Those promising developments followed the conclusion of a nuclear deal with Iran earlier in the year, agreement by 12 nations on the Trans-Pacific Partnership free trade deal, signals that Russia seeks to play a positive role in the Middle East, and steps toward peace talks in Afghanistan. Myanmar appears to be on the path toward a political transition that heralds the arrival of democracy in that country. Even China, which concluded the year by reportedly sending an armed vessel into Japanese waters, has demonstrated in several ways — its stance at the climate talks, diplomatic activism in the Middle East and Central Asia — that it is ready to act as a "responsible stakeholder."

None of these processes are concluded; they are all works in progress, and as such they constitute the primary challenges of the year ahead. In addition to demanding hard work, patience and creativity, they also require a vision since the successful implementation of these deals and processes will restructure in important ways the architecture of the international order.