The family of Trinh Xuan Tung (his mother Nguyen Thi Cuc, his wife Nguyen Thi Mien, and his two daughters Trinh Kim Tien and Trinh Cam Tu) outside the court on July 17, 2012, waiting to attend appellate proceedings in the trial of former Col. Nguyen Van Ninh, convicted of causing Trinh Xuan Tung’s death. The poster features a picture of the perpetrator and slogans calling on authorities to impose a longer prison term.

The United States government made a mistake this month in relaxing a ban on lethal arms sales and transfers to Vietnam — a non-democratic, one-party state with an abysmal human rights record. The U.S. move, announced on October 2 as Vietnamese Deputy Prime Minister Pham Binh Minh was visiting Washington, undermines courageous activists in Vietnam and squanders important leverage that might have been used to encourage more reform.

U.S. officials claim that Vietnam is making small but significant progress on human rights, emphasizing recent releases of political prisoners. But most of the moves they cite are minor, and one of the most well-known prisoners released this year, a lawyer named Dr. Cu Huy Ha Vu, was not released but rather paroled into exile in the United States.

Indeed, the number of political prisoner detainees has increased in recent years, and today more than 150 dissidents are in detention. With the latest releases, the most one can say is that the Vietnamese government is operating a revolving door in which old political prisoners are replaced by new ones. And while the population in detention may ebb and flow, an alarming trend is now on the rise: the use of thugs to attack and intimidate critics.

In grading Vietnam’s reform, the Obama administration should analyze more than a head count of those detained and released, and consider contextual questions. If Vietnam is really serious about reining in persecution of peaceful critics, then why did its courts convict three activists in August (Bui Thi Minh Hang, Nguyen Thi Thuy Quynh, and Nguyen Van Minh) for “obstructing traffic” during a protest and sentence them to three years in prison? Why did the government arrest the prominent blogger Nguyen Huu Vinh (Anh Ba Sam) in May? Why did Vietnam convict the blogger Pham Viet Dao in March? And why have the authorities convicted almost ten ethnic Montagnards at various points through the year, for supposed crimes against the state?

The larger question about Vietnam is whether the government really demonstrated that it is serious about making systematic changes to allow its citizens greater freedoms. Has Hanoi taken any meaningful steps or shown any real willingness to undertake legal reforms to remove penal code provisions criminalizing political speech? Have Vietnamese leaders taken any meaningful steps or shown any real willingness to undertake legal reforms to allow independent trade unions? Has Vietnam taken any meaningful steps or shown any real willingness to deregulate and decriminalize independent religious activity, or stop persecution of religious minorities? The answer to each of these questions is no.

Unfortunately, the decision to relax the lethal arms ban has already been made. It is not too late, however, to use remaining leverage to achieve change. Given the absence of real reform to date, and the major steps that remain to be taken, the U.S. should communicate to Hanoi that it expects much more before the ban will be lifted further.

The United States should now tell Vietnam that future transfers and sales beyond maritime assistance will only occur if Vietnam releases a substantial number of political prisoners; takes more rigorous steps on issues like religious liberty, torture, and labor rights; and makes formal moves to repeal political crimes from its penal code, like Article 87 of the penal code, criminalizing the act of “undermining the unity policy,” and Article 258 “abusing democratic freedoms” to “infringe upon the interests of the State.”

The U.S. government can and should make these points clear in talks later this year in Hanoi, when Secretary of Defense Chuck Hagel is set to visit. These messages could also be enhanced if coordinated with messages from the U.S. Trade Representative (which is negotiating with Vietnam in the context of the Trans-Pacific Partnership) that Vietnam cannot expect to join the trade pact unless it undertakes legal reforms to allow independent trade unions.

It is not too late to salvage U.S. leverage in the wake of the premature decision of October 2 to relax the lethal arms ban. For the sake of Vietnam’s brave dissidents, the U.S. should try to drive a harder bargain.

John Sifton is the Asia Advocacy Director for Human Rights Watch. Follow on Twitter at @johnsifton.