Although the TPP wasn’t an integral part of the US-Japan relationship, it certainly represented a cornerstone for its future. It’s no coincidence that as soon as Trump said he would be leaving the TPP, Abe was on the first flight out from Narita. For Abe, the TPP was more than just an economic treaty, it was a strategic assurance and promise (which he had invested large amounts of political capital in) that the US-Japan Alliance was still a top priority for America.