Mr. Kasato, the district councilor, said that plainclothes officers picked him up from a church meeting on Feb. 8, threw him, hooded, into a car and clobbered him.
He said the men asked him for the evidence of election rigging he’d collected, and whether he had sent it to Mr. Wine’s party. He said, yes, he had.
Mr. Kasato, a 47-year-old father of 11, said that while he was chained to the ceiling, his feet barely touching the ground, military officers whipped him with a wire and pulled at his skin with pliers.
“It was a big shock,” he said. “I was praying deeply that I really survive that torture.”
In late February, Mr. Kasato was charged with inciting violence during the November protests in which security forces killed dozens of people — accusations he denies. He has been released on bail, but said he was still in intense physical pain, and that his doctors advised he seek medical attention abroad.
Analysts say that Mr. Museveni, 76, who has ruled Uganda since 1986, is trying to avoid history repeating itself. He himself was a charismatic young upstart who accused his predecessor, Mr. Obote, of rigging an election, and led an armed rebellion that after five years managed to take power.
Mr. Wine, 39, whose real name is Robert Kyagulanyi, has become the face of this young movement, promising to shake up the country’s stifled politics. As his campaign gained ground last year, he was arrested and beaten and placed under de facto house arrest.
“We are seeing a movement toward full totalitarianism in this country,” said Nicholas Opiyo, a leading human rights lawyer. He was abducted last December and released, charged with money laundering after his legal advocacy group received a grant from American Jewish World Service, a New York-based nonprofit.