The American Bar Association (ABA) Center for Human Rights has concluded that the ongoing treason trial and detention of Tanzanian opposition leader Tundu Lissu are “politically motivated” and “incompatible with international human rights obligations.”
In a comprehensive preliminary analysis released earlier this week, the ABA detailed systemic fair trial deficiencies, including the disproportionate use of treason charges and the wholesale granting of anonymity to civilian witnesses.
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Lissu, the national chairperson of Tanzania’s main opposition party CHADEMA, was arrested on April 9, 2025, during a political rally in Ruvuma. A practising lawyer, he was subsequently charged with treason, a non-bailable offence that carries the death penalty, and has remained in detention for over a year.
The ABA report focuses on three specific areas of concern: the treason charge itself, the use of anonymous witnesses, and the resulting restrictions on the right to effectively examine those witnesses.
The assessment was conducted using publicly available information and trial documents, as the ABA was unable to send independent trial monitors due to what it described as “the highly restrictive context in the country.”
READ MORE: UN Body Rules Tundu Lissu’s Detention Arbitrary, Demands Immediate Release
Several senior lawyers and civil society leaders from neighbouring countries had been previously detained and deported when attempting to observe the trial.
Disproportionality
The ABA analysis strongly criticised the application of treason charges against Lissu, arguing that it overly infringes on his right to freedom of expression.
The prosecution alleges that Lissu formed an intention to instigate the public to obstruct the October 2025 general election, basing the charge on a single short speech where he allegedly used the word kukinukisha, which authorities translated as a threat to “rebellion” or “civil disobedience.”
“In the case of Tundu Lissu, the application of Tanzania’s treason laws raises at least three areas of concern,” the report states.
“First, the charges overly infringe the right to freedom of expression. Second, treason is a non-bailable offence under Tanzanian law, and Lissu has been unable to challenge his ongoing detention as a result.
“Third, Tanzania’s treason law carries the death penalty as its maximum punishment, which constitutes a disproportionate and impermissible punishment under international law for speech-related conduct.”
The report notes that under international human rights law, public figures and governments must tolerate a higher degree of criticism than private citizens. The ABA found that Lissu’s alleged statement did not directly refer to the Executive, Legislature, or Judiciary, nor did it advocate violence or coercion.
“As such, it appears unlikely to satisfy the core statutory element of intimidation required under section 39(2)(d) [of the Penal Code], even on the prosecution’s own account of the speech,” the analysis concluded.
Anonymity
A significant portion of the ABA’s assessment focused on the Tanzanian High Court’s decision to grant anonymity to all non-police civilian witnesses. These witnesses have testified from obscured wooden boxes, a measure the ABA argues severely undermines Lissu’s right to a fair trial.
While international law permits witness anonymity in exceptional circumstances to protect safety, the ABA noted that it must be strictly necessary, proportionate, and accompanied by adequate procedural safeguards.
The report found that the wholesale granting of anonymity without individualised risk assessments failed to meet these standards.
“The wholesale granting of anonymity to all civilian witnesses, without individualised risk assessment, weighed against the significant restrictions on the accused’s fair trial rights, including a lack of procedural safeguards, indicates a likely failure to meet the strict necessity and proportionality requirement,” the report stated.
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“This blanket approach, particularly in a death penalty case, suggests the measures fail to properly balance competing factors to the detriment of Lissu’s right to a fair trial under international human rights law.”
The use of anonymous witnesses testifying from enclosed spaces has materially impaired Lissu’s ability to effectively cross-examine them, according to the ABA.
The report highlighted that assessing a witness’s demeanour is a key component of evaluating credibility, particularly when testimony concerns the subjective interpretation of speech.
“Effective cross-examination in accordance with fair trial standards would require not only the opportunity to ask questions, but the ability to meaningfully test credibility and reliability,” the analysis noted.
Pattern of repression
The ABA’s findings align with previous international condemnation of Lissu’s detention. In February 2026, the UN Working Group on Arbitrary Detention (WGAD) issued a decision finding that the treason charges constituted a “grossly disproportionate restriction on freedom of expression” and held Lissu’s detention to be unlawful.
The ABA report places Lissu’s prosecution within the broader context of the October 2025 general elections, which saw incumbent President Samia Suluhu Hassan declared the winner amid widespread allegations of state-sponsored violence, mass arbitrary detentions, and extrajudicial killings targeting opposition figures and civil society.
READ MORE: Tanzania’s Top Court Frees Opposition Party CHADEMA After 309-Day Ban
The organisation reports that the arrest of political opponents and journalists has become increasingly common in the country, raising serious concerns about the erosion of democratic norms and the weaponisation of the judicial system to silence dissent.
“In addition to these specific potential violations, the overarching narrative must also be considered,” the ABA concluded. “Tundu Lissu is Tanzania’s most high-profile opposition political leader, who was detained in the months leading up to a general election.
“Within the context of this timeline, and the widely reported violent government crackdown on opposition supporters, the cumulative evidence suggests that Lissu’s arrest, detention, and prosecution are politically motivated and incompatible with Tanzania’s obligations under international human rights law.”
