Is the person who believes in Allaah The Almighty as well as in a Taaghoot a disbeliever?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.

Islamic monotheism is based on believing in Allaah The Almighty and disbelieving in a Taaghoot (any entity that is worshipped besides Allaah, be it a devil, an idol, a tree, a shrine or any other thing). However, a person who is worshipped against his will incurs no sin, such as ‘Eesa (Jesus) and his mother, may Allaah exalt their mention, and many other prophets and righteous people. In this regard, Allaah The Almighty Says (what means):

It was reported that the Prophet, sallallaahu ‘alayhi wa sallam, said that both the property and life of a Muslim are inviolable if he testifies that there is no god except Allaah, and disbelieves in whatever is worshipped besides Him; and Allaah The Almighty would hold him accountable for his intention. [Muslim]

Hence, the property and life of a Muslim are not prohibited unless he gives this testimony as well as disbelieves in whatever is worshipped besides Allaah The Almighty. Disbelief in any Taaghoot is the actual realization of the negation included in the Testimony of Faith: “There is no god but Allaah”.  

Such was the religion of Ibraaheem (Abraham) . Allaah The Almighty Says (what means): {There has already been for you an excellent pattern in Ibraaheem and those with him, when they said to their people, "Indeed, we are disassociated from you and from whatever you worship other than Allaah. We have denied you, and there has appeared between us and you animosity and hatred forever until you believe in Allaah alone"} [Quran 60: 4]

The true believer in Allaah The Almighty must disbelieve in Taaghoot, otherwise, his faith would not be sound. However, there are those who believe in the lordship of Allaah The Almighty (i.e. that He creates and sustains), yet associate others with Him in worship, such as the polytheist regarding whom Allaah The Almighty Says (what means): {And most of them believe not in Allaah except while they associate others with Him.} [Quran 12: 106] They testify that Allaah The Almighty is the Creator and the Sustainer, yet they worship others, and their faith as such would never benefit them.

Allaah Knows best.