In recent months, Mr. Mugabe has been cranking up his party’s election-time machinery of control and repression. He appointed all the provincial governors, who help him dispense patronage and punishment, rather than sharing the picks as promised with Mr. Tsvangirai. And traditional chiefs, longtime recipients of largess from his party, ZANU-PF, have endorsed Mr. Mugabe as president for life.

Political workers and civic activists who lived through the 2008 campaign of intimidation and repression  in which many foot soldiers in Mr. Tsvangirai’s Movement for Democratic Change were tortured or murdered  say ZANU-PF will not need to be so violent this time around. Threats may be enough.

In Mashonaland West, Mr. Mugabe’s home province, people said they were already being warned by local traditional leaders loyal to Mr. Mugabe that the next election would be more terrifying than the last one, when their relatives were abducted and attacked after Mr. Tsvangirai won some constituencies.

“They say, ‘We were only playing with you last time,’ ” said one 53-year-old woman, too frightened to be quoted by name, repeating a warning others in the countryside have heard. “ ‘This time we will go door to door beating and killing people if you don’t vote for ZANU-PF.’ ”

But even as many voice a growing conviction that Mr. Mugabe is plotting to oust his rival and reclaim sole power, he has retained his ability to keep everyone guessing. His political opponents and Western diplomats wonder if Mr. Mugabe is bluffing about a push for quick elections, perhaps to force the factions in his own party to declare their allegiance to him and extinguish the internal jockeying to succeed him.