The Gospel of Jesus Christ is the Good News that Jesus Christ, the Son of God, atoned for our sins and resurrected from the grave so that we all will rise in resurrection and stand before Him to be judged. We will inherit a kingdom of glory (with a few exceptions). Those who exercise Faith in Christ, Repent, are Baptized by His authority, Receive and live by the Holy Ghost, and endure to the end keeping the Commandments (Moses's 10 plus a few related others you'll find in your Temple Recommend interview or the Temple itself), will be joint heirs with Christ of all that the Father has. (See 3 Nephi 27:13-27; D&C 76; Romans 8:17) And this is available to all, living or dead. (See D&C 128).
Now, what the Gospel is not:
The Gospel is not a political party or politics in general. (I don't know how many times the Church needs to keep saying this!)
The Gospel is not economic theory.
The Gospel is not philosophy.
The Gospel is not even theology. (Think about that one in context of the previous one. And I don't care if you're a liberal or conservative theologian. That says nothing about how you live your life before God).
I understand that most people don't distinguish in this way. I also understand that it is human nature to wrap one's core values around our interpretations within some of these systems as much as we do our religious belief and they sometimes get confused.
Go back to the first paragraph, please. Nothing else matters.