The May and September reciprocal state visits by U.S. President Donald Trump and China’s President Xi Jinping have seemingly succeeded in cementing warm personal ties between the two leaders while stabilizing an unstable U.S.-China relationship. Historians may look back on these twin summits as perhaps a turning point following a decade of tumult and steadily intensifying competition between the two powers. While the two summits have succeeded in warming the atmosphere, there remains much substantive and institutional work to do.

The relationship is likely to remain characterized by the dynamics of cooperation and competition—with friction and coordination coexisting for the foreseeable future. The primary role for heads of state will not be to produce dramatic breakthroughs but rather to build trust.

The two countries need to establish their Zeus’s Law, preventing strategic rivalry from escalating without limit and avoiding the idea that undermining the other side’s sense of security can somehow serve as a source of one’s own security.

China-U.S. relations face both opportunities and challenges. At least within this year, and particularly given the three forthcoming meetings between the two heads of state, the opportunities outweigh the challenges as relations continue to move forward.

For China, a prerequisite is characterizing the overall kind of relationship the two sides have before specific issues can be discussed. The United States has often taken the opposite approach, starting with results in specific areas, then expand. Now the two sides seem to be nudging closer.

The meeting of two presidents created a certain degree of stability and opened up possibilities for cooperation, but China-U.S. relations remain fundamentally fragile. Nudging the relationship in a constructive direction will require that both countries continue in good faith.

Trump’s trip to China signals the start of a new trade relationship, anchored in good economic fundamentals that are solid, stable and sustainable. Both countries stand to benefit, as does the rest of the world in terms of peace and prosperity.

Trump’s high-stakes visit to China against a backdrop of conflict with Iran and economic tit-for-tat exchanges have made those issues the central focus for observers, but the shift in the U.S. President’s tone on Taiwan’s defense may be just as consequential as any deal that emerges.

The May 14-15 summit meeting in Beijing between Presidents Xi Jinping and Donald Trump resulted in some badly needed stabilization in bilateral relations. Both the symbols and the substance of the visit suggest a return to some normalcy of regularized interactions and the ability of the two leaders and their teams to discuss some of the most sensitive issues between the two sides. Even if detailed agreements are not reached (and not many were) there is still considerable value in such direct exchanges.

China-U.S. relations involve the well-being of some 8 billion people worldwide. Both sides, therefore, need to safeguard their hard-won stability. They should honor their commitments and move toward each other to create favorable conditions for building a more promising future.