The two world powers that have been bumping up against each other with increasing frequency in Asia-Pacific waterways held a much-needed dialogue this week, during which top officials put on smiles and agreed to disagree.

US Secretary of Defense James Mattis and Secretary of State Mike Pompeo met in Washington with their Chinese counterparts, Defense Minister Wei Fenghe and top foreign affairs official Yang Jiechi, where they discussed North Korea, Iran, the South China Sea, and Taiwan.

Pompeo said in a joint press conference following the two-day dialogue that, despite differences on a wide range of issues, there remain areas for cooperation, including on North Korea. He also made a point to mention the importance the US places on getting China to reduce oil imports from Iran to zero, a commitment Beijing has emphatically said it will oppose.

There has been some speculation, including from news website Axios last week, that some form of cooperation from China on the Donald Trump administration’s Iran policy is on the table in trade negotiations. Those trade talks, which have stalled as far as what has been made public, have a chance to see a breakthrough or at least be restarted when the two countries’ presidents meet in Buenos Aires this month.

In an attempt to push back on a commonly held view in Beijing, Pompeo tried to offer reassurance that “the United States is not pursuing a cold war or containment policy with China.”

Despite his insistence that the talks were extremely productive, there was no room for agreement on issues that have led to rising tensions in recent weeks.

Top on that list is the South China Sea, where warships from the two countries recently had a near-collision, and Taiwan, where the US has been signaling a policy shift with more frequent arms sales and the sailing of ships near the island.

Defense Minister Wei reiterated during the press conference that China would take any necessary measures to ensure the eventual unification of Taiwan is not threatened, a statement in response to the sailing of a US warship through the Taiwan Strait for the second time in several months.

Politburo member Yang bluntly told the US to stop sending ships and aircraft near China-claimed territory in the South China Sea. Mattis responded that the US would “fly, sail and operate wherever international law allows.”

Pompeo and Mattis also told China to stop militarizing the islands in the South China Sea.

Despite the persistent disagreements, the show of constructive engagement, which stood in contrast to a frosty interaction between Pompeo and Chinese State Councilor Wang Yi in Beijing last month, reflects how, no matter how bad the relationship gets, divorce is not an option.