On Friday, Japanese Prime Minister Yoshihide Suga will become the first foreign head of state to meet in person with President Biden. Headlines have pegged military and trade relations as leading topics for discussion. Far fewer have called attention to the ongoing saga of Greg Kelly, an American citizen being held hostage in the Japanese justice system.

Mr. Kelly would have stood trial alongside Carlos Ghosn, the former CEO of Nissan who stunned the world in 2018 by fleeing Japan on a daring overnight flight to his native Lebanon. Unfortunately, Mr. Kelly is not as famous or well-resourced as his former boss, so his case is less well-known.

Greg Kelly of Tennessee began his decades-long career with Nissan in 1988. A loyal employee, he rose steadily in the ranks and became the first American to join Nissan’s board in June 2012. But what should have been a success story took a dark turn in 2018, when Mr. Kelly was lured to Japan by a Nissan executive under false pretenses and arrested upon his arrival.

Private emails show that the executive who lured him was colluding with Japanese prosecutors to disrupt a merger between Nissan and Renault, a French auto company. Mr. Kelly was helping negotiate the merger and was therefore a target to be neutralized. He was swiftly framed for bogus financial crimes and thrown under the bus by Nissan. Mr. Kelly strongly denies any wrongdoing in the matter. Notably, the Japanese employees who worked hand-in-hand with him on the merger were never indicted.

Because he was unfairly targeted, Mr. Kelly had to endure “normal” prison conditions in Japan for 34 days. He was kept in solitary confinement in the dead of winter, where he slept on the floor with no heat and with the lights constantly on. He was interrogated daily for hours at a time without the presence of a defense counsel. His requests for medical attention were refused, and his spinal condition — which was bad upon his arrival — predictably got worse. He was eventually allowed to have surgery in Japan, but the delay caused long-term pain and numbness in his extremities.

For the last 28 months, Mr. Kelly has lived under house arrest in a Tokyo apartment with his wife, who has relocated to be with him. Their children, on the other hand, live in the U.S. and have had limited access to their father, who is now 64. Mr. Kelly has missed several important milestones, including the birth of a grandson. 

His legal situation is a nightmare. Japanese officials have refused to let him and his lawyers review electronic documents they plan to use against him in court. A fair trial is out of the question, particularly since the chief witness in the case — Carlos Ghosn — has fled the country. Mr. Ghosn insists that Mr. Kelly is innocent and has described him as “an honorable man, husband, and father who was brutally ripped from his family.” Because criminal trials in Japan move at a snail’s pace, it could be years more before a verdict is reached — an injustice unto itself.

Mr. Kelly’s plight is a cautionary tale for Americans thinking about working in Japan. It is abundantly clear that non-Japanese executives who run afoul of Japanese norms can face inhumane treatment and an unforgiving legal system. Indeed, Mr. Kelly’s case is only the latest and most high profile among foreign nationals who have found themselves singled out and hunted by Japanese justice. 

This troubling double standard is not lost on many even within Japan. In 2019, more than 1,000 Japanese academics and lawyers signed a letter organized by Human Rights Watch criticizing Japan’s “hostage justice” system. These signatories understand that what happened to Mr. Kelly is an embarrassment to their country. The world expects kangaroo justice from Vladimir Putin, not from a free and modern democracy.

Mr. Biden and Mr. Suga may not discuss the plight of Greg Kelly when they meet, but many in Congress are already doing so. Japapn, for its own sake, needs to right this wrong and bring an end to this highly visible stain on its international reputation.