FAIR is a non-profit organization dedicated to providing well-documented answers to criticisms of the doctrine, practice, and history of The Church of Jesus Christ of Latter-day Saints.
Question: Why did the Nauvoo City Council feel it was necessary to destroy the ''Nauvoo Expositor''?
Question: Why did the Nauvoo City Council feel it was necessary to destroy the Nauvoo Expositor?
One member recorded that Joseph told him that the destruction of the press was necessary for the Saints’ safety
It is claimed that Joseph "could not allow the Expositor to publish the secret international negotiations masterminded by Mormonism’s earthly king." 
The reality was that the Joseph and the City Council were concerned that the paper would cause turmoil among the Saints.
One member stated,
Brother Joseph called a meeting at his own house and told us that God showed to him in an open vision in daylight [meaning that this was not something he had just conjured up in dreams of the night] that if he did not destroy that printing press that it would cause the blood of the Saints to flow in the streets and by this was that evil destroyed.
Joseph foresaw his own death as a result of the turmoil that was already occurring
Given Joseph’s numerous presentiments of his own death, it may well be that he knowingly chose this course of action to spare the members’ lives at the cost of his own. Said Joseph to Elizabeth Rollins:
I must seal my testimony with my blood.
Some has supposed that Br Joseph Could not die but this is a mistake it is true their has been times when I have had the promise of my life to accomplish such & such things, but having accomplish those things I have not at present any lease of my life I am as liable to die as other men.
- Richard N. and Joan K. Ostling, Mormon America: The Power and the Promise, (New York:HarperCollins Publishers, 2000), 16. ( Index of claims )
- Truman G. Madsen, Joseph Smith the Prophet (Salt Lake City: Bookcraft, 1989), 114; citing Diary of George Laub, BYU Special Collections, 18.
- Journal of Mary Elizabeth Rollins Lightner, BYU Special Collections, 7; cited by Truman G. Madsen, Joseph Smith the Prophet (Salt Lake City: Bookcraft, 1989), 103.
- Joseph Smith, Discourse of 9 April 1842, Wilford Woodruff Diary; cited in Andrew F. Ehat and Lyndon W. Cook, The Words of Joseph Smith: The Contemporary Accounts of the Nauvoo Discourses of Joseph Smith, 2nd Edition, (Salt Lake City: Deseret Book, 1996), 112.