BANGKOK — A prominent Vietnamese legal scholar and human rights campaigner who has called for multiparty democracy was due in court on Monday in Hanoi, facing up to 12 years in prison in a case that has mobilized unusually broad public support.

The defendant, Cu Huy Ha Vu, 53, has been in prison since November, charged with antistate propaganda for posting critical articles on the Web and giving interviews “maligning party and state institutions and policies,” according to the government.

Mr. Vu, who holds a law degree from the Sorbonne in Paris, has impeccable revolutionary and cultural credentials. His father was a prominent poet who was a colleague of Ho Chi Minh. His mother was a personal nurse for Ho Chi Minh.

He runs a law firm in Hanoi with his wife, has spoken out on a variety of politically delicate issues and has filed lawsuits twice against the prime minister. In 2006 he nominated himself, unsuccessfully, to become the minister of culture, a post held by his father in the Communist Party’s first provisional government in the 1940s.

Mr. Vu is the latest of dozens of Vietnamese lawyers and activists arrested over the past five years for challenging the government. His case, along with the continued detention of many other dissidents, suggests that a crackdown many analysts had seen as a prelude to a Communist Party congress in January may not have eased.

Mr. Vu’s case “may well evolve into one of the most important cases involving a political dissident in the recent history of the Socialist Republic of Vietnam,” Human Rights Watch said in a report released on Saturday.

The case pits an unusually well-connected legal activist against highly placed political figures, and it touches on a variety of human rights issues including police misconduct, arbitrary detention, violations of privacy, land grabbing, neglect of due process and repression of freedom of expression, the report said.

The case has spread across the Internet, drawing support from political bloggers, academics, journalists, Communist Party members and the general public.

Roman Catholic churches have organized prayer vigils and have sent flowers to Mr. Vu’s wife in gratitude for the stands he has taken in defense of parishioners. Bloggers have urged the public to gather at the courthouse, even providing a map to the surrounding area.

“An unprecedented movement of popular support,” Human Rights Watch said, “has emerged and continues to grow on the Internet. Indeed, the case provides reasons for optimism within the typically bleak human rights environment of Vietnam.”

An irrepressible commentator and irritant to the government on social issues and questions of human rights, Mr. Vu joined a broad-based protest against a controversial Chinese-built bauxite mining project in the Central Highlands by suing Prime Minister Nguyen Tan Dung in 2009 on the grounds of environmental damage, national security and cultural heritage. The lawsuit was quickly dismissed in the courts.

Last year, he sued the prime minister again for signing a decree that prohibited class-action lawsuits. No official response to that lawsuit has been reported.

At the time of his arrest, officials said Mr. Vu had “produced documents that opposed the State of Vietnam, employed propagandistic rhetoric as a form of a psychological warfare, demanded the overthrow of the regime and the realization of pluralism and a multiparty system, opposed the interest of the nation, and called for foreign intervention.”

He was accused of “producing documents that spread false and fabricated information, distorted the leadership and management of the state; causing confusion for the people; and provoking, advocating for and exhorting against the state, and slandering and offending the honor of the leaders of the state,” the government said.

His arrest appeared to be part of a tightening of controls throughout 2010 on freedom of expression, including the harassment and arrest of writers, political activists, lawyers and bloggers. Dissident Web sites were disabled by digital attacks, and new regulations restricted the use of public Internet cafes. Public protests over evictions and the confiscation of church property were put down by force.

A number of analysts viewed the crackdown as part of a campaign to set limits on public debate before January’s Communist Party congress.

On a visit to Hanoi in October, Secretary of State Hillary Rodham Clinton said, “The United States remains concerned about the arrest and conviction of people for peaceful dissent, the tax on religious groups, the curbs on Internet freedom, including bloggers.”

Mr. Vu appeared to operate independently of political groups and organizations, but his connections with high-ranking public figures, including powerful members of the Communist Party, and his family’s strong revolutionary and cultural credentials gave him a high public profile.

His father, Cu Huy Can, was a government minister and a member of Vietnam’s first National Assembly in 1946 as well as a pioneer in the modern Vietnamese romantic poetry movement in the early 1940s. His mother, Ngo Thi Xuan Nhu, was the sister of Xuan Dieu, one of the country’s most famous poets.

Though he is not registered to practice law in Vietnam, the firm Mr. Vu runs with his wife has taken on controversial issues. A year ago, although he is not Catholic himself, he took a high-profile stand in defense of Roman Catholic parishioners who were arrested for taking part in a funeral at a cemetery located on land claimed by the government.

On Tuesday, his family published an open letter online urging people to attend his trial to “witness a man of fairness and integrity being tried.”