Whichever non-American TV channel I watch or news site I read, everyone is either afraid of or is dumping on US Republican Party frontrunner Donald Trump.

The billionaire is the nightmare your sensitive mother and high-minded history teacher warned you about. He is a racist, foul-mouthed, hates women, supports torture, killing the wives and children of terrorists, he hates Muslims and wants to lock them out of America, he has said he will build a wall between the US and Mexico and keep Hispanics out, he doesn’t believe in free trade. The man is awful on everything.

Yet, disaffected Republican voters love him, and it will take something out of this world to stop him.

In some ways, Trump is America’s answer to Uganda’s nasty tyrant Field Marshal Idi Amin and Central African Republic’s “Emperor” Jean-Bedel Bokassa, the man who allegedly had schoolchildren arrested and 100 of them beaten to death for refusing to buy uniforms from a company belonging to one of his wives.

However, to rail against Trump and to invest so heavily in his defeat is to take a short-term view of the world.

The thing is that evil and bad men sometimes serve a useful purpose. The present world order is still largely a response to the horrors of World War I and World War II.

At global and national levels, we don’t usually carry out reforms through the inspiration of saints like Nelson Mandela or Mother Theresa.

We don’t say, “Mandela was an inclusive leader and left power after just one term, so let us revise the constitution so presidents will rule for only one term.” We only introduce term limits after someone has ruled for too long. Tanzania introduced term limits, after the otherwise benign Julius Nyerere had ruled the country for nearly 25 years before stepping down.

The years of madness leading up to President Yoweri Museveni capturing power in Uganda in 1986, persuaded a constituent assembly dominated by his ruling NRM to write term limits into the 1994 Constitution.

Rwanda too internalised the murderousness of the genocide in 1994, and decided that term limits were critical and set them in its 2003 Constitution.

Both countries, Uganda in 2005, and Rwanda last year, rediscovered their faith in men and removed term limits.

The post-election violence that followed the December 2007 general election in Kenya, the worst in the country’s post-independence history, gave birth to the fairly progressive 2010 Constitution.

A madman like Trump in the White House, with the button to the world’s most nuclear arsenal in the briefcase under his bed, will force the world to think in new ways about global security.

If Trump goes about slapping revenge tariffs on China and other economic rivals unilaterally, then the world trade order will have to be renegotiated.

If he builds a wall and puts a gun to Mexico’s head to pay for it, and sends jet fighters to bomb villages to kill the wives and children terrorists left behind, then America’s assumed role as the “leader” of the free world will collapse.

And all global moral institutions, the United Nations most definitely, will have to be reorganised. The world and nations don’t reform when they are comfortable. They only do so when they are afraid or have been severely injured.

Bring on Trump.

Charles Onyango-Obbo is editor of Mail & Guardian Africa (mgafrica.com). Twitter@cobbo3