In the smoky, near-darkness of the ramshackle schoolhouse that served as a barracks for the Georgian army, I huddled against the wall listening to the sputter of machine guns and the deep throaty boom of mortar shells.

"I believe you speak English," said a soldier sitting next to me, his face barely visible above his sweat-stained flack jacket. "I'm from the United States."

My neighbour, one of several hundred weary troops who joined the fight against separatists in western Georgia in 1993, was not only American but also a professor at an Ivy League university. And he told me: "When my country is threatened, I put down the books and pick up my gun."

He was not alone in his desire to fight for the country of his birth, despite a comfortable life in a new land. Even when guns fall silent, the fog of war often hangs heavy over the new countries where diaspora populations from far-flung conflict zones have settled.

But in the 21st century, when global migration affects nearly every country and one in every 35 people on the planet is an international migrant, it would be naïve to expect that what happens in the old country stays in the old country – or the country of one's forbears.

Toronto's recent Tamil demonstrations, protesting the killing of civilians in a Sri Lankan military operation against the Tamil Tigers, ignited new controversy over the limit to which diasporas can continue their struggles in Canada. The burning of a mainly Sinhalese Buddhist temple sparked fearful and furious reactions from those who declared that "foreign conflicts" had no place here.

The media, too, have been caught up, as cyberspace sizzles with angry diatribes from both sides.

The Sri Lankan conflict is not unique. As electronic communication burgeons, so have journalists' email baskets and Twitter lists, overflowing with complaints or entreaties from pro-Israeli and pro-Palestinian groups, Serbian and Kosovar exiles, Iranian dissidents and advocates for Armenia, Tibet, Burma, Afghanistan, Somalia, Darfur and Haiti – to name a few.

While some diasporas have been actively engaged in reconstruction, development and peace-making in their original countries, others are more hardline than the people they left behind, and the polarized debates they arouse make it more difficult to find accommodation or peace.

"Politics these days is often acted out by populations who are geographically removed from the sites of conflict," notes a paper by Camilla Orjuela of the University of Gothenburg in Sweden. "But although politics is to a large extent `deterritorialized' – it can be carried out (no matter) where you are – it has not ceased to be about territory."

Diasporas have the power to shape debate at home and abroad, to push local politicians to take part in international events and to use their money to support political or military movements that can change history for better or worse.

In some cases their power increases in their adopted countries, where they have less direct influence but more, and safer, access to communication tools. And for dissidents who oppose dictatorial regimes, it is easier to defend human rights while staying out of range of murderous revenge.

But political lines may also harden as distance increases. And as years go by, second- and third-generation diasporas may be most adamant, and inflexible, about a solution for their families' homelands, which they see in idealized terms.

They also lack one of the main ingredients of settlement: the sheer war weariness that takes over when one or both parties have suffered enough destruction.

Some Irish-descended Americans, for example, backed the IRA's violent campaign for a united Ireland, while the exhausted population of Northern Ireland, both Catholic and Protestant, were ready for a peace process that was forged in compromise.

The difficulty diasporas may have in coming to terms with less-than-ideal solutions is clear. The 250 or so conflicts simmering throughout the world guarantee that they or their families will have fled quickly, with few resources and deep psychological wounds. Their view of their familial countries is flash frozen in an agonizing moment of time.

"For years I woke up screaming," a young Rwandan-born woman who lost her family in the genocide told me. "It was something I lived with. In the daytime I could feel normal, but at night it was different."

The first generation of traumatized refugees spends its lifetime coping with the horror of murder, torture, ethnic cleansing and violent seizure of their homes. Their nightmares are passed on to their children and grandchildren, who suffer their own forms of trauma, including the guilt that comes from leading double lives, inside and outside of their own families and communities.

Multiculturalism – encouraging communities to preserve their own cultures, languages and traditions – fosters pride, but may make adaptation more difficult for the young, who receive mixed messages. Some soothe their sense of alienation by identifying with the struggles in their parents' homelands, creating an ideal future from a sometimes-mythical past.

Loading... Loading... Loading... Loading... Loading... Loading...

Even in the U.S., where the melting pot trumps multiculturalism, emotional attachment to a cultural "motherland" remains. The diasporas have long arms, supporting "foreign" struggles through lobbying and fundraising for their causes.

"It's the most important work I could do right now," said an impeccably dressed American businessman smoking in the lobby of a rundown Albanian hotel during the 1999 Kosovo conflict. Of Albanian descent, he had come to hand over funds raised for the guerrillas who were battling the Serbs for an independent state. And he said, he would continue until the fight was won.

It's a sentiment that many feel about many national causes. And one that is questioned by others who see no room for "dual loyalty." But in the new transnational landscape, where boundaries are virtual as well as real, identity has taken on a new dimension. And so have the conflicts that once seemed so far from our shores.