Is it a sin to pledge allegiance to a queen?

[victorianus]

I feel so uneasy to invoke God in my wordly affairs. However, the Catechism of the Catholic Church states that Catholics may give an oath for grave and right reasons.

Following St. Paul, the tradition of the Church has understood Jesus’ words as not excluding oaths made for grave and right reasons (for example, in court). “An oath, that is the invocation of the divine name as a witness to truth, cannot be taken unless in truth, in judgment, and in justice” (CCC 2154).

What constitutes grave and right reasons? May I swear during the Canadian citizenship ceremony and pledge my allegiance to the British queen? In a court case (e.g. as a witness for petty crime), is it better for me to replace the word “I swear” with “I promise” or “I affirm”?

 

[Michelle_Arnold]

The Catechism itself has given you an example of acceptable instances for giving an oath when it states “for example, in court.” So, yes, you may indeed be sworn in for a court case, even one that is adjudicating a petty crime or a civil suit. As for the citizenship ceremony, that is a legal event also and so you may be sworn in and pledge allegiance to a head of government.