As our Ryanair flight from Pisa descended into Edinburgh through rain clouds, I was already thinking about next year's holiday.

One week in the Italian sun had spoiled me for the uncertain summer here.

Then came the devastating news from Tunisia: 38 holiday makers massacred at the last count, at least 30 of them British. Two Scots are dead and two missing.

Sometimes there are no words. I looked at the pictures of those ordinary, unsuspecting people. I thought how they must have counted down the days to their holiday, how they would have shopped for sun cream and maybe fretted that last year's swimsuit seemed to have shrunk in the cupboard.

They would have organised their currency and most of all they would have felt that lift of the spirits as the date arrived. I can imagine their growing sense of excitement. What an awful tragedy awaited them.

The obituaries are woven from the strands of everyday families: James and Ann McQuire enjoying their recent retirement; 54-year-old grandmother Claire Windass who was celebrating her husband's birthday; Sue Davey and Scott Chalkley, who'd just bought a house; Carly Lovett, just 24, who died in her boyfriend's arms. Days before she had tweeted: "Definitely leaving in like three hours and definitely am not finished packing."

There were no presidents, prime ministers or military chiefs among the dead. These were the softest of targets.

It was this utter vulnerability of the victims that shocks most. They were prone, as naked as any of us gets in public, and relaxed, unguarded and undefended.

What we do about this brutal attack, what our national response should be, will be decided in Downing Street. But since this assault was on people like us, shouldn't we too think about how we will react. Should we, for example, ever return to the beaches of Tunisia?

The instinctive response is no. Why put ourselves and those we love in harm's way? Why go to a place with such painful memories? Wouldn't it be disrespectful of our innocent dead if we continued to go there?

But maybe before we make a knee-jerk and understandable decision, we should understand why IS has targeted Tunisia. While this was largely the act of a lone gunman, there was cold method in it.

IS wants to destabilise Tunisia precisely because the country is a success story for democracy, the birthplace of the Arab Spring. Tunisia is an example of how secular parties and moderate Islam can co-exist. It is therefore a challenge to this extreme sect's desire for a caliphate; for its barbaric writ to rule.

Tunisia's economy relies significantly on tourism. It accounts for 14 per cent of its gross domestic product. There are 400,000 people directly employed in tourism with a further 1 million dependent on it.

If tourists boycott the country, Tunisia will become weaker. Unemployment and poverty will rise, the very conditions where extremism thrives. So IS's target was as strategic as it was soft.

If British tourists holiday elsewhere, we will demonstrate two things to these monstrous people. The first is that we fear them. The second is that we prefer to see them destabilise a decent country than to face them down.

Now that is easy to write. It is harder to act upon. How do parents square that logic with loading their children onto a plane for two weeks in Tunisian sunshine? If they do, will they have a moment's rest from worry? Or will they be policing their children even as armed beach guards watch over the tourists?

As someone who believes in democracy and loathes the mind-set of extremists of any kind, I hope we take that risk in ever increasing numbers. In the same spirit we climbed aboard American flights after 9/11 and returned to the London Underground after 7/7.

After all, are we any more at risk from a lone gunman in Tunisia than we are in France or London for that matter?

Our world is risk-laden. Take a look at the Foreign Office advice to travellers if you doubt it. Among the countries where the terrorist alert is high are the popular destinations of Turkey, Thailand, Spain, Egypt and France. Ireland, Norway and Portugal are said to have an "underlying threat". Italy and Greece have a "general threat". Switzerland is low.

The United Kingdom's own risk of a terrorist incident is severe, one below the top rating of critical. I certainly pass through stations such as King's Cross or airports with a heightened sense of alert.

But - and here's the dilemma for all of us choosing a holiday destination - in changing our behaviour because of the threat of terrorism, we can unwittingly hand power to the enemy. IS is clever with its imagery. Their masked faces and flying black flags put me in mind of pirates who roamed the high seas, a skull and crossbones flag designed to strike terror. But, unmasked, they are just hated filled hooligans on a rampage.

I like the approach of Tim Collins. He calls them a death cult in whose name mass murder was committed in Tunisia. He describes the beach as a crime scene, not a war zone.

Instead of focusing on the lone gunman and those who might have assisted him in his killing spree, shouldn't we focus on the dozen Tunisian hotel staff who formed a human shield between the gunman and the tourists? We should remember the worker who risked his life to stay holding the hand of an injured woman. We should recall the builders who threw roof tiles and bags of cement in an attempt to stop the killer, as well as the policemen who shot him down.

It is decent people like these who will suffer if we abandon their country; people very much like the victims killed and wounded on the beach. So perhaps we have to stand up for what we believe in by noting the risk and booking our tickets to Tunisia anyway.

This summer, being a tourist throws up difficult moral dilemmas. Take Greece as another example. The issue is very different than the one confronting holidaymakers who have booked a week on the beach at Sousse. But the outcome if we stay away from the country because of the financial and political crisis it is suffering could have a similar effect. If the country is destabilised any further, there is a danger of civil breakdown and of violent extremism.

Greece relies on tourism even more than Tunisia. It accounts for one fifth of its income, or 23 million tourists a year, at least three million from Britain. The country is in a terrible mess with a prolonged recession and years of hardship in prospect.

If it also loses its tourists, what is to become of its people?

We talk about ethical tourism in terms of how we behave to others when we are guests in their country. Isn't this another variation on ethical tourism: pitching up to support the people whose side we are on when they are under threat?