trojan-horse

US /ˌtroʊ.dʒən ˈhɔːrs/
UK /ˌtroʊ.dʒən ˈhɔːrs/
1.

Trojaans paard

a person or thing that joins and deceives a group or organization in order to attack it from the inside:

:
Conservative Republicans have called the amendment to the bill a trojan horse, designed to stop the bill from passing.