The most extreme consider co-operation with state institutions to be kufr, or unbelief.

一些最极端的人则考虑与国家机构合作，成为为kufr，即无信仰人士。

youdao

In general, referring judgment to non-Islamic law is disbelief in Allah (kufr), according to the explicit statements in the Qur'an.

CENTERFORSECURITYPOLICY: Center For Security Policy

The foreword deals with governing by other than that which Allah sent down, and when it becomes disbelief in Allah (kufr).

CENTERFORSECURITYPOLICY: Center For Security Policy

However, it is the smaller disbelief in Allah (kufr).

CENTERFORSECURITYPOLICY: Center For Security Policy