THIS MAY, in a visit to Vietnam, President Obama announced he was lifting the embargo on selling lethal arms to Hanoi as part of an effort to normalize relations long after the Vietnam War. While celebrating Vietnam’s deepening economic and security ties to the United States, Mr. Obama cautioned that to really get ahead, it should respect freedom of expression, assembly and religion. “There are still folks who find it very difficult to assemble and organize peacefully around issues that they care deeply about,” he said.

It seems clear from Vietnam’s recent actions that the rulers in Hanoi did not believe they had to pay attention to Mr. Obama’s advice. On Oct 7, theydeclared that the California-based pro-democracy group Viet Tan, or the Vietnam Reform Party, is a terrorist organization and warned of severe penalties for anyone who contacted it. The group, which describes itself as a “pro-democracy organization working to promote social justice and human rights through nonviolent means,” said this was the first time it has been formally designated as terrorist under Vietnam’s laws. Three of the group’s members are serving long prison terms for their blogging and community organizing.

On Oct. 10, police in the south-central province of Khanh Hoa arrested a popular blogger, Nguyen Ngoc Nhu Quynh, 37, who writes under the pen name Mother Mushroom. She is co-founder of a network of independent bloggers who often find themselves in the crosshairs of a regime that strictly controls the news media and does not tolerate dissent. Radio Free Asia quoted the network as protesting that Ms. Quynh is an “activist who has advocated for human rights, improved living conditions for people, and sovereignty for many years.”

Most recently, Ms. Quynh had been blogging extensively about a chemical spill in April that devastated marine life and left fishermen and tourism industry workers jobless in four provinces. In June, a Taiwanese-owned company acknowledged it was responsible for the pollution and pledged to clean it up, but the spill has provoked protests by Vietnamese who criticize the government for remaining silent about the cause of the spill at the outset and then failing to provide information about health and environmental dangers. Many of the protests were mobilized on Facebook.

When taken into custody, Ms. Quynh was accused of publishing “propaganda” against the state. A police statement said she had posted a report compiling 31 cases in which civilians died in police custody, which showed “hostility towards the police force.”

When Mr. Obama visited in May, it was clear that security cooperation and normalization of relations were on the front burner as the United States and Vietnam face an increasingly aggressive China. It is notable that Vietnam also agreed to economic and labor reforms required by the Trans-Pacific Partnership. But these are not sufficient. Vietnam also must free its people to blog, protest and speak out without fear.