President Obama with Nguyen Van Hai, better known by his pen name Dieu Cay, in May. (Alex Wong/Getty Images)

FOR THE people of Vietnam, still repressively ruled by a single Communist party more than 40 years after the fall of Saigon, inclusion in the Obama administration’s proposed Trans-Pacific Partnership trade deal presents both peril and opportunity. The concern is that freer trade and closer economic ties between the United States and Vietnam will strengthen the regime while providing this country with an incentive to shrug off its human rights violations. The hope is that deeper engagement with the world’s largest capitalist democracy will nudge Vietnam’s rulers toward greater political openness.

For the time being, Vietnam seems to be experiencing a relaxation of political control, not quite worthy of the name “spring,” but possibly rising to the level of a thaw. According to civil society leaders, the Hanoi leadership is loath to commit spectacular abuses in the midst of negotiations over the TPP lest it lose support in the United States, where the inclusion of a low-wage, authoritarian state is already controversial. Therefore, Vietnam released 50 of 160 prisoners of conscience last year, and it mostly has limited its harassment of dissidents to shorter-term arrests and detentions.

This is hardly to be confused with genuine liberalization, as a visiting group of civil society activists sponsored by Voice , a regional human-rights organization, told us in a recent meeting. Anyone attempting to establish a nongovernmental group in Vietnam is still routinely denied legal recognition; some are beaten, albeit by plainclothes men, not the uniformed officers of the more brazen past. As journalist Nguyen Van Hai, one of the political prisoners released last year after six years behind bars, told us, Vietnam’s communists also relaxed their grip a decade ago while pursuing membership in the World Trade Organization — only to crack down again when the United States and other nations moved their attention elsewhere.

For all that, the human rights advocates expressed cautious support for TPP. Given that Vietnam’s rulers seem divided over a variety of policy issues, foreign and domestic, and given their need for U.S. support against a regionally ambitious China, Hanoi is perhaps more susceptible to outside suasion than at any other time in recent history. Depending on the strength and enforceability of TPP’s provisions calling for signatories to respect trade-union independence and other basic rights, the agreement could bolster those struggling for freedom. It may give their demands an even firmer basis in international law and make it harder for U.S. officials to turn a blind eye to violations when they occur. In short, though fundamentally an economic instrument, TPP could have positive political repercussions, as long as U.S. leaders are willing to hold Vietnam’s regime accountable.