The 2019 trade deal agreed by the US and China saw few concrete outcomes, offering lessons for this week’s summit, a prominent economist told Semafor.

Beijing and Washington must “establish something that is achievable” to avoid the pitfalls of the prior pact, the Peterson Institute’s Chad Bown said: China committed to buying $200 billion in additional US exports, but ultimately purchased none of what it agreed to.

The 2019 deal halted a trade war, but the commitments were “completely unrealistic,” Bown said. Still, he isn’t dismissing this summit as purely political theater: A Board of Trade mechanism, for example, could improve communication and ensure the transactions actually happen, he said.