Anti-corruption campaigns in several European countries have experienced such a severe backslide over the course of the last year that they may breach international standards for fighting bribery and graft cases, according to the latest annual report by the Council of Europe’s 49-member Group of States against Corruption (GRECO).

The Council has initiated proceedings against Serbia, Belgium, Hungary, Ireland, Luxembourg, Portugal, Romania, Spain, and Turkey as a result of GRECO’s findings, wh...