Liu Xia, the widow of Nobel-winning Chinese dissident Liu Xiaobo, arrives at the Helsinki International Airport in Finland on Tuesday. (Jussi Nukari/Lehtikuva via AP)

WHEN CHINESE poet and artist Liu Xia arrived in Helsinki on Tuesday en route to a new life in Berlin, she spread her arms wide in a gesture of freedom. Few have sacrificed as much in the name of that ideal as Ms. Liu and her late husband, Nobel Peace Prize laureate Liu Xiaobo. Mr. Liu was arrested in 2009 for defending democratic principles and died in captivity exactly one year ago, after Chinese authorities refused to let him travel abroad for cancer treatment. Ms. Liu, meanwhile, was kept under unofficial house arrest for eight years in an attempt to intimidate her husband and maintain her silence.

Though she was never charged with a crime, Ms. Liu was forced to live under constant surveillance and had limited contact with the outside world. Western governments repeatedly called on China to free her, with concern mounting in the past year amid reports that her physical health and mental health were deteriorating. Her release to travel to Germany was a welcome culmination of months of diplomatic efforts.

However, anyone hoping that her release would herald a shift in China’s persecution of dissidents was soon disappointed. On the very same day, an independent think tank in Beijing that espoused free-market and pro-democracy positions was evicted from its offices. Long viewed as a bastion of liberalism, the Unirule Institute of Economics has faced growing pressure from the government. Regulators already shut down its social media pages and website; now, without a physical location, its future is in doubt.

Hours later, Chinese courts sentenced the prominent activist Qin Yongmin to 13 years in prison on bogus subversion charges. As part of the evidence against him, prosecutors cited his role in founding a human rights organization and an article he wrote calling for Beijing to respect the Universal Declaration of Human Rights. Mr. Qin, who has been campaigning for democratic change in China for more than four decades, has already spent a total of 22 years in prison or forced labor camps. For the 64-year-old, the new sentence could amount to life in prison — a gross injustice for someone whose only crime was to engage in free speech.

Mr. Qin joins more than 1,400 known political prisoners who are currently detained, according to a database run by the Congressional-Executive Commission on China. Among them are Wang Quanzhang, a human rights lawyer who was arrested in 2015 and has not been seen or heard from since; Ilham Tohti, an ethnic Uighur professor; and Gui Minhai, a Hong Kong bookseller and Swedish citizen.

The successful effort to free Ms. Liu shows that sustained, unwavering pressure on Beijing can yield results. Democratic governments must continue pushing China on its dismal human rights record and particularly its brazen crackdown on free thinking and dissent. The European Union can start by bringing up the cases of political prisoners at the E.U.-China summit in Beijing next week.