On Saturday, Nigerians will go to the polls to choose their president. The race pits an incumbent with an imperfect record against a former military dictator who has flirted with Islamism.

As with the recent election in Israel, alumni of Obama are aiding the challenger -- and not because he would make the region safer.

The decision Nigerians will make this weekend matters greatly, both for themselves and the West. Nigeria has Africa’s largest economy, with a gross domestic product of about $500 billion. It is a major energy producer and exporter, but also a political and cultural bellwether: the nation of 177 million is divided almost equally between Christians and Muslims.

Nigeria’s problems are serious, ranging from endemic corruption to a spiraling jihadist insurgency. The economy is growing but the unemployment rate exceeds 20 percent. Transparency International, which ranks nations by the absence of corruption, places Nigeria at an undesirable 136th out of 175.

Far more concerning, Boko Haram, the foremost jihadist group in Nigeria, has waged a bloody Islamist insurgency. This month, the group’s leader pledged allegiance to ISIS, whose own reach now includes parts of North Africa.

The challenger in Saturday’s election, Muhammadu Buhari, blames incumbent president Goodluck Jonathan for these problems. Buhari recently remarked, “if Nigeria does not kill corruption, corruption will kill Nigeria.”

That sounds appealing: corruption repels foreign capital and creates misery for those without privilege. But Buhari’s medicine may be worse than the disease.

His prescriptions range from the facile, like passing a whistleblower law, to the dangerous, like expanding the use of sharia -- Islamic law that is enacted and enforced by clerics rather than democratic institutions.

There is a real risk that a Buhari-led Nigeria would take the same path of Turkey over the last decade. There, a populist leader, Recep Erdogan, has fanned the flames of Islamist sentiment to augment his power. In so doing, he has transformed Turkey -- nominally a member of NATO -- into an ally in name only.

Turkey now hosts leadership elements of Hamas and the Muslim Brotherhood and has aided attacks on Israel. What was once an iconic Muslim-majority nation that embraced modernity and separated mosque and state is now an antagonist of those virtues.

An “Erdogan” scenario in a divided country like Nigeria might lead to sectarian war. Even if that extreme outcome is avoided, the West and its partners might still lose a democratic ally in the struggle against radical Islam.

Of course, this is a struggle that the Obama administration famously refuses to acknowledge -- either in Africa or anywhere else. President Obama’s summit last month on countering “violent extremism” was remarkable only because it avoided a discussion of the force that animates so many of civilization’s violent and extreme enemies: radical Islam.

This ignorance explains many of Washington’s mistakes in Nigeria and the fight against Boko Haram. When the jihadist group drew western attention by kidnapping 276 schoolgirls, first lady Michelle Obama reacted for the administration with an absurd Twitter campaign.

Her husband later ordered a pittance of troops to train Nigerian forces -- enough to claim action but not enough to effect any tangible result.

Repeating a pattern seen in other struggles against tyranny, the Obama administration has refused to send serious military aid to those who are willing to fight for themselves -- in this case the Nigerian military. Instead, the White House has critiqued the Nigerians about human rights, apparently unaware of the irony of giving a lecture on humanity to those struggling against some of the most evil and inhumane jihadists on earth.

Assessing the motives of these decisions isn’t difficult. The political firm founded by Obama’s former chief strategist, David Axelrod, reportedly supports and advises Gen. Buhari’s party.

This is reminiscent of the involvement of Jeremy Bird, Obama’s 2012 field director, in Israel’s election this month. Whether these services are performed for love or money is anyone’s guess, but it fits a pattern of an Obama administration waging political warfare against allies who have made White House policies look bad.

All of this should matter to the West and our allies because we are engaged in a global struggle against the forces of radical Islam. This is a fact whether or not our leaders choose to recognize the struggle. Regions whose problems could once be lamented but ignored because of their limited relevance now matter when they affect this contest.

Nigeria itself is a perfect example. What was a shocking but isolated insurgency is poised to metastasize into a regional conflict: Chad and Cameroon have recently seen it necessary to join the fight. Political or military failure in Nigeria will make the struggle against radical Islam much harder.

Many Nigerians have understandable qualms with President Jonathan and his quest for a second term. However, he has demonstrated new resolve in the fight against Boko Haram. Crucially, Jonathan also has a commitment to secular democracy and modernity that his opponent lacks.

Hopefully Nigerians reject the dubious promises of a pro-sharia populist, while delivering another defeat for a feckless White House that likes to tamper in the elections of democratic allies.

Christian Whiton is the president of the Hamilton Foundation and the author of “Smart Power: Between Diplomacy and War.” He was a State Department senior advisor during the George W. Bush administration