An appeals court in Vietnam has upheld the 7-year prison sentence for the dissident son of one of Vietnam's founding revolutionaries.

Defendant Cu Huy Ha Vu, a human rights lawyer educated in France, was found guilty earlier this year of spreading propaganda against the state. The finding came despite Vu's arguments that his calls for political pluralism were not intended to undermine Vietnam's communist government. He said he only demanded a multi-party system aimed at fostering political competition.

Ahead of Tuesday's ruling, prosecutors had argued that Vu's actions violated national security and abused freedom of speech.

Since 2009, Vu has tried twice to file lawsuits against Prime Minister Nguyen Tan Dung, accusing Mr. Dung's environmental policies of violating laws and the Vietnamese constitution. Vietnamese civil courts rejected the cases and Vu was arrested late last year during a crackdown on dissidents ahead of a ruling party congress. Mr. Dung was elected to a new five-year term as prime minister last week.

Vu is the son of Cu Huy Can, a widely admired poet and member of the first provisional Cabinet established in 1946 by independence leader Ho Chi Minh. He had defended various dissidents including Catholics, but was long thought to be safe from prosecution because of his connection to ruling party officials.

In April, at Vu's initial one-day trial, one of his lawyers was expelled from the court and three others walked out in protest after a judge rejected their demands to see documents being cited as evidence against their client.

The U.S. State Department said later that the conviction “raises serious questions about Vietnam's commitment to rule of law and reform,” and urged the government to release him immediately.

Tuesday, the deputy Asia director for Human Rights Watch said he believes Vietnam's communist leadership had sought to make an example out of Vu. Phil Robertson said Hanoi appeared intent on conveying the message that Vu's attempts to question government policy will not be tolerated. He also said the government risked appearing less than resolute if it considered any reduction in the original sentence.