"背离党规者" can be translated into English as "those who deviate from party regulations" or "individuals who stray from party rules".
Here are some variations depending on the context:
"Violators of party regulations" (if emphasizing the act of breaking the rules)
"Defectors from party discipline" (if emphasizing a complete departure from discipline)
"Those who go against party rules" (a more literal and straightforward translation)
The most common and neutral expression would likely be "those who deviate from party regulations", as it accurately conveys the idea of moving away from or not adhering to the established rules.