Failed presidential candidate Senator John McCain advised President Donald Trump to rejoin the Trans-Pacific partnership trade deal.

“It’s easy to punish China. It’s a lot harder to hold it truly accountable and change its behavior,” the senator wrote on Twitter. “That requires a real strategy and positive trade agenda, which is why the US should rejoin the #TPP11.”

TPP-11 is the new version of the free trade partnership in Asia after Trump withdrew from the deal because it wasn’t fair to the United States.

McCain criticized Trump for withdrawing from the TPP trade deal, during a May speech in Australia calling it a “serious mistake.”

Trump indicated in January that he’s open to the idea of rejoining the TPP if he could make “a substantially better deal” than Obama’s effort.