The likes of Robert Mugabe in Zimbabwe prefer monitors from the African Union, who in the past have endorsed suspect results (they have recently become a bit more rigorous).
More ambitious places, such as Kenya and Ghana, crave the imprimatur of the European Union and respected American outfits, notably the National Democratic Institute, the International Republican Institute and the Carter Centre.
Nowadays foreign monitoring teams start to arrive a good month before the big day and stay for at least a month after it.
The outsiders help in several ways.
They provide expertise on technology, especially concerning the registration of voters and the method of vote-counting.
Monitors also help co-ordinate “parallel vote tabulation”, whereby samples of the results from randomly selected polling stations are collected and presented quickly to prevent fraud in the later counting process.
Crucially, foreign monitors support local watchdogs who do most of the work and face the greatest risks.
Foreigners alone cannot ensure fair elections.
They rely on the co-operation of local governments, to gain access to the entire process, including the voters' register.
But they can raise the bar against rigging.
Beyond constraining the incumbents' power, their scrutiny can build popular trust in the elections—and make it easier for losers to accept defeat.
It is an expensive business, but worthwhile.
Worryingly, the Trump administration is trying to slash the State Department's budget which helps support democracy, including election monitors.
Congress is right to resist such cuts.
Fair elections make Africa more stable.
Giving up on them spreads anger and poison around the world.