In dark times, exile can be a choice for an individual. It can also be a weapon for a repressive regime."As a global-facing activist, the choices I have are stark: to stay silent from now on or to keep engaging in private diplomacy so I can warn the world of the threat of Chinese authoritarian expansion."Those are the words of Nathan Law, a 26-year-old Hong Kong activist. He posted them on his Facebook page on July 2 as he announced he was going into exile to an undisclosed location.The trigger for his decision was the new security law passed by the Chinese National Congress, which sweeps Hong Kong under Beijing's iron umbrella.Already, the law is having an effect, with hundreds arrested after protests against it. One of those arrested was a 16-year-old girl. She had been waving a Hong Kong independence flag.The draconian law makes subversion, collusion with foreign forces and preaching secession punishable with sentences up to life in prison.WATCH | Hong Kong activist Nathan Law goes into exile:For activists like Law, that points to a bleak future. Thus, the choice of exile and "private diplomacy."The decision to 'remake your life'It was a choice that hundreds of thousands were forced to make in the 20th century. Jews and many others fled Hitler's Germany in the 1930s. Hungarians in 1956 and Czechs and Slovaks in 1968 fled their countries as the Soviet Union crushed attempts at revolt and reform.Almost 38,000 Hungarians and 12,000 Czechs and Slovaks were received as official immigrants to Canada in the wake of those events.The Soviet empire started to fall apart 21 years after the Soviet-led invasion of Czechoslovakia, but only a small number of those who went into exile in 1968 returned.My wife is Czech, and over the years, I have met many Czechs who left in '68 and never returned."It's very hard in exile to remake your life once," said one, who preferred for me not to include his name. "But to do it twice in middle age or older, even returning to your own country, was just too much."Exile can also be a weapon, one with a long history.In the fifth century B.C., the city-state of Athens imposed 10-year sentences of exile ― called ostraka, or ostracism ― by a vote of its citizens on people considered dangerous to its democracy.One of ancient Rome's greatest poets, Ovid, was sent into exile to a town on the shores of the Black Sea in modern-day Romania by the emperor Augustus. His crime is unknown.Ovid only referred to it as "carmen et error" – poetry and error. He begged to return, but his poetry and his unexplained error were such that the emperor never forgave him. He died in exile.No choice but to leaveModern totalitarian regimes regularly have recourse to use exile as a weapon. The Soviet Union forced two future dissident Nobel Prize winners for literature into exile ― Alexander Solzhenitsyn and Joseph Brodsky.Many others received the same treatment, including Marina Voikhanskaya, who is a friend.She is 85 and lives in Cambridge, England. Forty-five years ago, she was working as a psychiatrist in Leningrad (now St. Petersburg), Russia. The KGB, then Russia's security police, pressured her to sign forms assessing a poet she knew as insane.He held dissident views. If she signed the forms, he would be confined to an asylum and drugged. It was a punishment used frequently."You can't imagine how scared I was when I wrote my opinion," she said. "I cried for two hours before I refused to sign, because I knew my life would go to pieces."It did. She was harassed, dismissed from her post and forced into exile. But the Soviet regime held her young son in the U.S.S.R. It took a four-year public campaign in Britain to pressure Moscow to allow him to join his mother in 1979."At the time, I didn't think I would miss my country," Voikhanskaya said recently. "But for five years, there wasn't a day when I didn't think of it, and miss it."Although the Soviet regime collapsed, she has never gone back, and says she never will. "Now, I don't see myself as an exile but as a Russian living in England."The Chinese approachChina has also used exile as a weapon, most notably against the artist Ai Weiwei. Many of his art installations were critical of the regime in Beijing.In 2011, he was arrested and held in a small cell for 81 days, watched by video cameras with the lights on 24 hours a day. After his release, he was charged with tax evasion. Finally, in 2015, his passport was returned to him and he was sent into exile. He now lives in Europe and continues to do work critical of Beijing.One famous dissident turned the tables on the Chinese regime, by refusing exile.Liu Xiaobo was studying abroad when the massive student demonstrations against the Chinese communist government broke out in 1989. He flew back and became a leader of the revolt. But when it was crushed by the People's Liberation Army, he stayed, unlike many other student leaders.Liu became a public critic from within — for his pains, he was arrested, sent to prison and frequently put under house arrest. I met Liu in 2008, just before the Beijing Olympics. It was a week before the anniversary of the 1989 Tiananmen Square massacre, which left an estimated 3,000 dead. As in previous years, Liu was under house arrest but he demanded to see his lawyer. He was driven to his lawyer's office by the security police.I was interviewing his lawyer, Mo Shaoping, when Liu walked in.Liu described his position with sardonic humour, comparing the regime's changed approach. "When I was arrested in 1996, they ransacked my house and left it in a mess. In 2004, they came and searched again. But this time, they all wore white gloves, and they put everything back. And they chauffeur me to my appointments," Liu said."You can't win a trial in the end, but the legal process is much improved since the 1990s. Still, you can't call it 'the rule of law.' The rule of law we have now is only better than the rule of law in Mao Zedong's time, when we had no rule, no law."No end in sightHis words were prophetic. Six months after our meeting, Liu was arrested again, just before he was about to release a "charter of human rights and democracy.""We should end the practice of viewing words as crimes," the charter said. The regime disagreed.A year later, Liu was convicted of "inciting subversion of the state's power" and sentenced to 11 years in prison. In 2010, he won the Nobel Peace Prize.Liu died of cancer in July 2017. His request to receive treatment in exile was rejected.Indeed, Beijing now seems to prefer not to use exile as a weapon but rather to keep its opponents at home and under arrest.The latest person to suffer this treatment is Xu Shangrun, a Beijing professor and outspoken critic of the regime. On July 6, he was arrested and accused of consorting with prostitutes. "It's just the kind of vile slander that they use against someone they want to silence," Geng Xiaonan, a friend of Xu's, told the New York Times.The 20th century regimes that forced so many to flee into exile are no more. Nazi Germany was destroyed by war. The Soviet Union succumbed to economic collapse. The agitation and ideas of exiles played a role in the deaths of these regimes ― but a secondary one.At the moment, China doesn't seem vulnerable to those menaces. The life of Nathan Law and others in exile may be long and frustrating.