Liu Xia, center, wife of jailed Nobel Peace Prize winner and Chinese dissident Liu Xiaobo, holds a portrait of him during his funeral in Shenyang, China, on July 15. (Shenyang Municipal Information Office via Associated Press)

“EVEN IF I am crushed into powder, I will embrace you with ashes.” So wrote Chinese dissident and Nobel Peace Prize laureate Liu Xiaobo about his wife, Liu Xia, as part of a statement he composed for trial in 2009. Ms. Liu, a photographer, painter and poet, steadfastly stood by her husband as he called for democratic freedoms in China — and faced relentless persecution for it. Now, even after his death , it is becoming clear that this persecution is not at an end.

Ms. Liu has been kept under unofficial house arrest since 2010. Though Chinese authorities have claimed she is “free,” she has been made to live under constant surveillance. She is rarely allowed to leave her home, and few visitors are permitted entry. Her mobile phone service was disconnected seven years ago, and she has had limited contact with the outside world ever since. These conditions, along with the deaths of both her parents and now her husband, have taken a toll: Ms. Liu is reportedly suffering from depression, and both her physical and mental health are deteriorating the longer she is held in isolation. Friends and family have been unable to contact her since her husband’s death, raising new concerns about her well-being.

Is there no limit to the cruelty China’s rulers are willing to deploy in their unending quest to squelch and punish free speech and free thought? Surely Ms. Liu has suffered enough. She watched as her husband was imprisoned four times, eventually dying without the care he could have received outside of China. She saw her younger brother face harassment, too: In 2013, Liu Hui was sentenced to 11 years in prison in a clear attempt to pressure her. His arrest prompted Ms. Liu to make one of her few public statements since her forced isolation: She shouted, “I am not free.” She is not and will not be until China stops its hounding of an innocent family.

Secretary of State Rex Tillerson issued a statement on the day of Mr. Liu’s death calling on Beijing to release Ms. Liu from house arrest. And although President Trump came under heavy — and deserved — criticism for exuberantly praising Chinese President Xi Jinping that same day, he also reportedly brought up the issue in a private phone call with Mr. Xi. Congress, meanwhile, is considering legislation to commemorate Mr. Liu while simultaneously urging Beijing to free his wife. These are all important efforts, and they need to be sustained.

In 2012, Ms. Liu said of her house arrest, “Kafka could not have written anything more absurd and unbelievable than this.” We agree. It is time for China’s Communist regime to leave this woman in peace.