What is the influence of Christianity on western political system?

Answer 1

The Pope authorised and confirmed the crowning of Charlemagne and subsequent Holy Roman Emperors. This became the feudal system with all it's attendant peerages and monarchies. Successors remaining today include all of the monarchies of Europe with the possible exception of the scandinavian monarchies.

Queen Elizabeth is a successor of William the Duke of Normandy, who was a noble of the French Capetian kings who were successors of the Carolingian nobility of the western half of the HRE.

Every modern European monarchy has a (Christian) state church and are crowned or authorized by the Church in some form or other. The English monarch is the titular head of the Anglican Church. One of the twin Princes of Andorra is the current Bishop of Urgell.

Western politics and Christianity are inextricably interwoven.

Answer 2

It provides the fundamentals that the western culture should be functioning under. But since it is not currently functioning that way; it is collapsing.

Answer 3

yes