When a Virgin Galactic test spaceship ripped up in space killing the pilot, here is what founder Richard Branson said about the future of his company's space tourism program. "Space is hard, but worth it." You might say that too of some wars. War can be hard and war can be messy.

But when you have to fight a war against terror, you can't call it off in the middle because your troops are taking losses. You'll be sending a gratifying message to the enemy and a terrible one to history about your cause.

Imagine if Abraham Lincoln, reeling at the sight of piling corpses early in the American Civil War, would have caved in, surrendered to the Southern states who wanted secession and even worse, the continuation of slavery. There would have been no Emancipation Proclamation to free black slaves or that dazzling quote "democracy is government of the people, by the people and for the people."

What about the crippling losses the Allies suffered from Hitler's blitzkrieg shock early in World War ll? Was this reason to capitulate, bow down to Hitler's terror and suck up to his tyranny?

This is what some people would have us do in Somalia. Bow down to al-Shabaab and quit in droves. It's bizarre and it misunderstands the logic of fighting wars, particularly wars of necessity.

President Obama, while running for the White House, memorably distinguished between a war of choice and a war of necessity. He opposed Bush's war in Iraq because it was a war of choice, one that America simply didn’t need - it didn't advance her interests or even that of humanity. But he backed the war in Afghanistan, the one that was in pursuit of Osama bin Laden and his co-conspirators in Kabul. That was a war of necessity which America was obliged to fight, even to the death. Honor, America's sovereignty and the destiny of democracy were all at stake. Indeed, there was overwhelming consensus from the world through a UN resolution.

It's the same with Kenya's war with al-Shabaab. Make no mistake, this is a war of necessity, and it must be won. Al-Shabaab threatens our sovereignty and that of neighbouring states. This war has international support, including that of the African Union. Al-Shabaab is hell-bent on a jihadist state possibly with global reach, in cahoots with the murderous ISIS. Only cowardice, unbelievable lack of principle or shocking ignorance of history can make you walk away from doing something about such an enemy who is your very neighbour  and poses an existential threat to  you .

Perhaps these words by President George Bush said just after the horrific September 11 attacks can make the quit-Somalia-crowd work up their nerve and discover their focus again. "A great people has been moved to defend a great nation....These acts (planes slamming into twin towers)  shatter steel, but they cannot dent the steel of American resolve."