A presidential campaign is a wide minefield of dangerous questions for candidates and their handlers. The tests of common knowledge are always risky. How many houses do you own? How much does a loaf of bread cost? If you love public schools so much, how come you sent your children to private ones?

Staff can quiz the candidate with some facts-of-life-outside-the-bubble flashcards. That’s just memorization. The revealing and ruinous ones for a lot of candidates are like this: “Are we right to feel utterly hopeless and helpless about Iraq?” veteran British radio presenter Jenni Murray asked Emma Sky, distinguished Senior Fellow at Yale’s Jackson Institute for Global Affairs, on Tuesday.

Sky spent 2003 to 2010 in responsible positions in Iraq in Afghanistan. A British citizen who opposed the 2003 invasion of Iraq, Sky worked closely with Iraqi civilians and American military leaders. She grew to respect and like the Americans in Iraq, finding them “honest and earnest,” striving to make a better life for Iraqis.

Sky, who’s written about her experience in “The Unraveling: High Hopes and Missed Opportunities in Iraq,” is armed for answers by experience and intellect. Her response to Murray reveals that we are right to feel utterly hopeless about the fate of Iraq. Sky hopes young Iraqis decide to create a future for themselves, but otherwise it’s “very, very depressing.”

We will expect something more substantial from presidential candidates. They are in the tricky business of wrapping reality in relentless optimism. Voters are not policy experts, but they know the difference between a serious answer and a dodge. The Islamic State (IS) army reigns in madness over a land mass in Iraq and Syria that is bigger than Great Britain.  We want to know what a candidate will do as president to confront the IS threat.

Intelligence services, still the object of considerable skepticism after blundering on whether Saddam Hussein possessed weapons of mass destruction, cannot agree even on how many soldiers are in the IS army. We do know, however, that thousands of Iraqi soldiers fled advancing IS troops, leaving behind another trove of sophisticated military equipment for IS to use.

Secretary of State John Kerry and White House spokesmen are channeling Vietnam era defense secretary Robert McNamara with their magical theory of brutal setbacks masquerading as advances. Voters will expect candidates to inject some realism. Dubious drug huckster and former Arkansas Governor Mike Huckabee will not be able to claim he’ll reverse IS gains like he did diabetes.

There’s a lot more than Iraq to address. Is chlorine gas a chemical weapon? President Obama danced around this at the Gulf Cooperation Council summit this month. Anyone aware it’s been dropped by brutal dictator Bashir Assad probably has a clear notion that it is. Do we go to war over that elusive redline?

Knowing how to identify and support a legitimate democratic movement in an oppressed nation, for example, requires more than a quip. It’s not enough to point out the Obama administration’s failures. Tell that town meeting of serious New Hampshire primary voters what you’d do as president.

The Russian reset has failed. We know that. Taking a swing at Hillary Clinton over her role in it is not a complete answer. Would you send more weapons into Ukraine? How much business do we conduct with regimes peppered with unsavory characters in high office? That’s an essay question.

How do you cope with a popular pope who embraces the communist dictator of Cuba but refuses to meet with the gentle and freedom loving Dalai Lama? North Korea appears to be getting closer to having small nuclear warheads that it can deliver to a target. There’s no quip for that, Senator Lindsey Graham.

For five uncomfortable days, Jeb Bush offered multiple confused answers on whether knowing what we know now he would have gone into Iraq in 2003. Another extended public display of befuddlement like that and Bush could find clever Carly Fiorina overtaking him in some surveys.

Foreign policy messes are covered with Hillary Clinton’s fingerprints. They are among the issues keeping her isolated in affluent Chappaqua. Republican hopefuls can’t hide. Responding to the public’s appetite for candid answers is both risk of failure and opportunity for victory.