With the Republican and Democratic parties set to hold their respective national conventions later this month, trade and Asian security have emerged as contentious issues for their presumptive presidential nominees, Donald Trump and Hillary Clinton.

Amid a populist surge in the United States in the run-up to November's presidential election, Trump has made his anti-globalization message a cornerstone of his campaign, including a threat to pull Washington out of the Trans-Pacific Partnership free trade deal. Clinton has also turned against the 12-nation deal she once championed.

Together with Trump's suggestion to withdraw U.S. forces from Japan and South Korea despite China's rapid military buildup and North Korea's pursuit of nuclear weapons, such a protectionist atmosphere has fueled concern among other TPP members and Washington's Asian allies that U.S. trade and foreign policy may undergo radical changes after President Barack Obama completes his term in January.