First, the words of an Apostle, spoken in General Conference, which we are taught means this is the word of the Lord:
"Communism introduced into the world a substitute for true religion. It is a counterfeit of the gospel plan. The false prophets of Communism predict a utopian society. This, they proclaim, will only be brought about as capitalism and free enterprise are overthrown, private property abolished, the family as a social unit eliminated, all classes abolished, all governments overthrown, and a communal ownership of property in a classless, stateless society established.
Since 1917 this godless counterfeit to the gospel has made tremendous progress toward its objective of world domination.
Today, we are in a battle for the bodies and souls of man. It is a battle between two opposing systems: freedom and slavery, Christ and anti-Christ. The struggle is more momentous than a decade ago, yet today the conventional wisdom says, “You must learn to live with Communism and to give up your ideas about national sovereignty.” Tell that to the millions—yes, the scores of millions—who have met death or imprisonment under the tyranny of Communism! Such would be the death knell of freedom and all we hold dear. God must ever have a free people to prosper His work and bring about Zion." - President Ezra Taft Benson, October 1979 General Conference
Second, an official statement by the First Presidency:
"We call upon all Church members completely to eschew Communism. The safety of our divinely inspired Constitutional government and the welfare of our Church imperatively demand that Communism shall have no place in America."
Third, the words of President David O McKay in the April 1966 General Conference:
"The position of this Church on the subject of Communism has never changed. We consider it the greatest satanical threat to peace, prosperity, and the spread of God's work among men that exists on the face of the earth."
Last (for now), a statement from Elder Dallin H. Oaks, just last month:
"Unpopular minority religions are especially dependent upon a constitutional guarantee of free exercise of religion. We are fortunate to have such a guarantee in the United States, but many nations do not. The importance of that guarantee in the United States should make us ever diligent to defend it. And it is in need of being defended."