The causes and consequences of the Great Famine of Ireland.
The potato blight hit the United States first before it came to Ireland (and other countries). But what made it particularly devastating in Ireland was the factor of human influence--behind-the-scenes bureaucracy that prioritized economics over human lives.
Prime Minister Robert Peel was caught between the political pressures of the Whigs and the Tories. He repealed the corn laws in Britain to keep food prices low in Britain, with the secondary goal of famine relief for Ireland, but that bureaucratic multi-tasking would not help the Irish very much...
Watching the Irish suffer from the view of London, Sir Charles Trevelyan believed that the potato famine was part of God's will. Inspired by the meritocracy-based philosophy of starvation that Thomas Malthus held, Treveylan created a relief plan with the sole goal of protecting the markets, and not the people. Thus the new year of "Black '47" brought chaos and horror to the Irish people.
Not all of the 214,000 Irish immigrants in 1847 made it safely to their new homes--and of those who did, many faced classism and xenophobia and even bullying from the "Ulster Irish" or "Scots-Irish" folks who had previously established themselves. In New York City specifically, the Five Points neighborhood became an infamous center of conflict--while local Irish-American John Joseph Hughes became instrumental in restoring Irish Catholicism.
Irish leaders entered the picture when the 1847 Poor Laws backfired, leading landowners to mass-evict their starving tenants. Daniel O'Connell tried to maintain an alliance with the Whigs, and failed. The Young Irelanders split off from the Repeal Association, and as a result, both the rebellious and the moderate minds of the country lost significant traction, unable to fight the famine alone.