The new ads by Donald Trump hammer undocumented immigrants and terrorism and pledge to make America safe again.

Making undocumented the equivalent of ISIS terrorists is yet another example of the focus of the Trump campaign aimed at hammering and demonizing those least able to defend themselves.

If you spend any time studying England and the world’s response to the Great Hunger in Ireland in the 19th century, you’ll be struck by the moralizing, the finger pointing and at worst the cold indifference -- not unlike the Trump dark vision today.

There is no doubt that Trump would have demonized the Irish fleeing the famine and turned back the antecedents of men like John F. Kennedy and Ronald Reagan, the father of Henry Ford and the father of Eugene O'Neill among millions  of others.

Back then like Trump's animosity to immigrants today it wasn’t enough that a potato crop had failed. Irish people were then scolded for their dependency on it. Pushed to the margins, cheated of their inheritance, they had had all their land stolen and were then blamed for the theft.

It takes a special kind of entitlement to blame the people your own ancestors robbed and defrauded for their enduring wretchedness, but Victorian England possessed it. On the ground accounts of terrific human suffering failed to move many of the far away policy makers in London, some of whom openly worried that all the reported deaths wouldn’t make a significant improvement to the Irish economy.

If the Irish were dying on the roads and their emaciated bodies were literally consuming themselves, it was because providence and God had debated their character and delivered His final judgment.

No need to get involved when God has decided who is marked for extinction. Better just to stand back and let destiny take its course. Especially if that destiny will quietly enrich you and make the governance of the place so much easier.

People who lived in well appointed metropolitan homes surrounded by servants, warmth and provisions in England could certainly feel themselves blessed by God. They shuddered at the ignominious condition of the Irish, but many told themselves it was their maker’s will. No need for further discussion.

I have always wondered about such people. It’s not the terrorists and mass shooters of this world that scare me. It’s the people who can turn their love and compassion off and on like a tap.

I used to wonder at the sheer scale of the human misery of the Great Hunger, which has been compared to a low level nuclear attack and was the worst human disaster of the 19th century in Europe.

How could fellow human beings stand by as one million men women and children starved to death and a further million took to coffin ships in the desperate quest to save themselves? At what point does your inaction become inexcusable, or if you believe in it, a sin?

Watching the recent refugee crisis in Europe, where tens of thousands fled their homelands in the Middle East and took desperate journeys on foot or by sea in a quest for survival, has been very instructive.

Persecuted at home and unwelcome where they landed, I see a little of us in them. I see frightened families in search of refuge.

I see human misery making an appeal to human compassion. The response has been reassuring or reprehensible depending on where those fugitives landed.

But what would have happened to us in the 19th century if the United States had taken the hardline on immigration that many European nations and America under Donald Trump wants to enact now?

How would our emaciated Irish forebears have fared under the so-called “extreme vetting” that Trump has just proposed? Trump has vowed to build a wall on the Mexican border and has promised a total ban on Muslims entering the U.S. He’s also threatened to suspend all immigration from countries with a history of spawning terrorists, a proposal that he repeated this week.

The 19th century Irish wouldn't gotten through his “extreme vetting.” Most likely we would have been subject to a total ban.

That's because at the time the Irish were deeply unpopular here in America. We were seen as dependent, priest-ridden, given to addictions of all kinds and wholly untrustworthy. We would never have gotten past a president who had singled us out for special opprobrium the way the nativist hordes on the New York streets once did.

The Irish who are still coming here now can quickly attest to the difficulties of the immigration program, as well as the expense and the years it takes to process. If Trump is serious about increasing the “extreme vetting” of intending immigrants then the gears of the whole process will slow dramatically, affecting the lives and livelihoods of millions, including us.

The U.S. issued more than 10.8 million visas to visitors last year -- which is up from 7.5 million in 2011 -- and it granted approval to more than 531,000 immigrants to enter the country.

If all of those people, and those who are still to come, are to face significant new hurdles then the work of Immigration and Customs Enforcement will be doubled, the lines will grow and the years of processing will grow with them.

In 19th century America gave a shot at a new life to a long suffering people who rewarded that generosity by enriching their adopted homeland economically, socially and politically. That's a journey we should always support. The hallmark of freedom is generosity, not fear, after all. Trump is only selling fear.

Emigrants landing at Ellis Island, New York: The 19th century Irish wouldn't gotten through Donald Trump's “extreme vetting.Getty images