For one thing, these factors are of a different quality - apples and oranges, so to speak.
For another, any generosity is exercised on behalf of the public, so it is public sentiment which should be the guide. Small wonder, then, that ministers were slow to open the nation's doors and are content to follow in the slipstream of the public and the press.
Still, waiting to follow public opinion can go badly wrong - as it famously did for Gladstone, who had to decide in 1884 whether to rescue General Gordon from Khartoum.
It all began with a holy war waged by a sect called the Dervishes who were keen to set up an Islamic state in the Sudan ruled by their leader, the Mahdi.
It sounds a little familiar, but there was an important difference from the current Isis campaigns. None of those who fled from the Dervishes were likely to end up at Calais or even at the Mediterranean coast - it was not in our backyard, not under our rule and not something on which Gladstone's Government was going to expend treasure and men.
Still, there were British citizens in the Sudan who needed to be evacuated and General Gordon was sent to see to it and then to withdraw.
In fact, he did evacuate about 2500 people but then, rather than withdrawing, he sought to maintain the garrison at Khartoum and, ultimately, got trapped there by the Mahdi's forces.
On March 12, 1884, he began, with a small force of Egyptians and Sudanese, to defend it with great bravery and skill in the hope that they could hold out until relief arrived.
The trouble was that no relief was on the way. The Government had instructed Gordon to organise the evacuation, not to drag them into a war. They, therefore, decided that the best thing was to do nothing, leaving Gordon to deal with the position as best he could.
The policy may have been excellent but, like current prime minister David Cameron in his initial reaction to the refugee crisis, they had overlooked something. Here the "something" was the popularity of Gordon himself.
A devout Christian, a hero who had suppressed the revolt in China, this was a man who led storming parties carrying only a cane, a man who fought against slavery.
His exploits had been well recognised and he was the darling of the public.
When the realisation dawned that Gordon was being left to die, the public reaction was overwhelming. Petitions were got up.
There was a vote of censure in the House of Commons and the press painted pictures of the Christian hero walking his battlements and looking to the north for the relief that would never come.
In the end, the Government changed its mind and a relieving force was dispatched up the Nile.
Alas, it was too late, arriving to find that Khartoum, after a siege of 317 days, had fallen two days before. Gordon was dead.
When the news got back to England, there was a huge outburst of popular grief, with special services, a day of mourning, statues and an epitaph written by Lord Tennyson.
The Government's position was impossible. By sending the relief force they had tacitly admitted that their earlier hesitation was wrong, but that hesitation had led to a disastrous result - they had simply waited too long. Shortly afterwards, Gladstone's Government fell.
It is to be hoped that Cameron's change of mind will be less disastrous but, however right it may be, it does not alter the need for a lasting solution. Something needs to be done to stem the crisis and that something will need troops on the ground.
They should, of course, be European troops - it is Europe that is threatened by the stream of refugees. The Middle East is in our backyard and we are the nearest neighbours.
If we do nothing, others will fill the void. Chaos and suffering have always offered opportunity to the aggressive.
Somewhere, deep in the Kremlin, Vladimir Putin must be wondering exactly when he should send troops to assist President Assad. It cannot be long now.
No doubt public opinion will force the European powers to do the same, but by then the Russians may have moved and much of the Middle East will have become a Russian fiefdom. As Gladstone found to his cost, one can delay too long.
John Watson is the editor of the UK weekly online magazine The Shaw Sheet - www.shawsheet.com - where he writes as "Chin Chin"