The sentence, handed down by an international panel of judges in The Hague, is considered significant for a number of reasons. Notably, Mr. Bemba was convicted even though he was far away from the militia fighting under his orders and was not present during any of the war crimes; the court said he was culpable because of his command responsibility. He should have halted or prevented the crimes, the judges said.
Mr. Bemba, who is now 53, was a businessman and scion of a prominent Congolese family before rising to the vice presidency — successful, rich and believed to be untouchable.
In 2002, he sent an expeditionary force of his political party, the Congolese Liberation Movement, into the Central African Republic to help put down a military coup there. Though Mr. Bemba rarely visited the troops, the judges at the International Criminal Court in The Hague found that he closely monitored their activities, and convicted him in March.
Sylvia Steiner, the presiding judge in the case, read out a summary of the court’s reasoning at the sentencing on Tuesday, saying that Mr. Bemba’s “knowledge of the crimes was unquestionable.” He did more than tolerate them, he deliberately “encouraged attacks on civilians,” the judge said.
The force of about 1,500 militiamen rampaged through towns on their path, claiming afterward that they had been poorly paid and that they were rewarding themselves by raping and pillaging.
The sentence given to Mr. Bemba heavily emphasized the militia’s unrelenting campaign of rape, “committed throughout the operation,” against women and men, adults and children. The judges cited instances of gang rape, and took note of the lasting physical and social harm that rape victims suffered, including stigmatization, ostracism and disease.
Because of the large number of rapes and what the judges called their particular brutality, rape as a war crime and a crime against humanity received more weight in sentencing even than murder — 18 years for the rape-related charges, with concurrent sentences of 16 years for murder and pillaging.
Prosecutors had asked for a 25-year sentence, and may appeal the sentence as too lenient, experts following the case said. Victims’ groups had asked for Mr. Bemba to be sentenced to the maximum possible penalty, without citing a specific figure.
Mr. Bemba had already been detained for eight years before and during his trial, so he would presumably now have 10 years left in his sentence if it stands at 18 years. It has been customary at international tribunals to deduct one-third of the total sentence, so Mr. Bemba may be eligible for early release in as little as four years.
Largely because of pressure from human rights advocates and women’s groups, organized or mass rape is increasingly being recognized and prosecuted as a weapon of war rather than as a byproduct of war. Other international courts have convicted defendants of rape as a war crime and a crime against humanity, but Mr. Bemba’s was the first such conviction by the International Criminal Court. In two earlier cases involving Congolese warlords, instances of rape were widely reported but not prosecuted.
In another twist, Mr. Bemba and four associates, including his former lead lawyer, are on trial in a parallel case at the same court, charged with trying to bribe witnesses in the war crimes case. Hearings in the contempt-of-court trial have been completed, and a verdict is expected later this year.
Witness tampering has become a major issue at the court, with allegations of bribery or intimidation occurring in almost every case so far. Some critics have called the contempt prosecution against Mr. Bemba and his associates a waste of time and resources, but lawyers who follow the matter say the court wanted to send a strong message by pursuing it.
In Kinshasa, the capital of Congo, members of Mr. Bemba’s political party, which he still heads, criticized the sentencing on Tuesday. “We will continue, and we will never cease, denouncing the selective justice of the I.C.C.,” Eve Bazaiba told a few hundred supporters, according to Reuters.
Géraldine Mattioli-Zeltner of Human Rights Watch said the sentence offered a measure of justice to victims in a country where armed groups have preyed on civilians with impunity for more than a decade.
Ms. Mattioli-Zeltner, who recently visited the Central African Republic, said that “many grave crimes, including the systematic use of sexual violence, remain unpunished” both there and in Congo.
More than 5,000 civilian victims participated in the court proceedings and may be awarded reparations payments. Judge Steiner said the court would deal with reparations in a separate ruling.