Coronation Oath
I'm not sure HM has done all she can to uphold her Oath and many people I talk with think she has in fact broken it.
You can read the Oath here
Coronation Oath, 2nd June 1953
The specific parts that concern me and other monarchists are where the Queen swears to govern the people of her realms "according to their respective laws and customs" - Signing the Treaty of Lisbon has given away the sovereignty of the United Kingdom to the Europeans
The other part is regarding the Protestant Reformed Religion. The Queen is the Supreme Governor of The Church of England, and she swears to the utmost of her power to maintain the Laws of God and the true profession of the Gospel. HM swears to the utmost of her power to maintain in the United Kingdom the Protestant Reformed Religion established by law. She swears to maintain and preserve inviolably the settlement of the Church of England, and the doctrine, worship, discipline, and government thereof, as by law established in England.
Over consecutive governments during her reign and General Synods of the CoE, drastic changes have been made to the Anglican Faith and secular laws that undermine the Oath HM took to defend the Faith.
In fact in 2012 she is still styled as 'Defender of the Faith'
As an Anglican, it is a difficult pill for me to swallow and I fear much worse under Charles.
In fact this was the very reason the Queen's family was brought to the UK many years ago, and the Act of Settlement is a manifestation of this fact
The Queen is not a politician and to take such a solemn Oath before the Archbishop of Canterbury carries a huge burden and IMO, I don't think the Queen has done all she can to honour her Oath.