The program was not merely halted due to politics, the system itself had some very real issues even at the end.
The Cheyenne originally suffered from a dangerous rotor instability at high speeds that destroyed a wind tunnel asset and subsequently a flight test article and its crew.
A control system modification was derived to remedy this situation late in its history and yielded a very smooth flying machine without the stability issues above ~220 kt, however the system was extremely complex and prone to multiple independent failure modes that were catastrophic.