Burundians on Thursday will vote in a referendum on sweeping constitutional reforms that would shore up the power of President Pierre Nkurunziza and enable him to rule until 2034.

With opponents cowed, beaten, killed or living in exile, there seems little doubt the amendments will pass, enabling the 54-year-old — in power since 2005 — to remain in charge for another 16 years.

The campaign period, like the preceding three years of unrest triggered by Nkurunziza’s controversial but ultimately successful run for a third term, has been marked by intimidation and abuse, say human rights groups.