We should be involved because our Lord demands it. In Matthew 5:13ff, in a passage appropriately referred to by many as our "Cultural Mandate", we are told "you are the salt of the earth; you are the light of the world." Salt and light influence. They change an environment. Salt, especially in pre-refrigerant days, retarded the decay and corruption of meat and other food items. Only a Christian, an image-bearer of Jesus Christ, an ambassador of His majesty, can properly restrain evil in our society.
We should also be involved because of our heritage. I am reminded of the Canadian poet Lt. Colonel John McCrae's great work In Flanders Fields when he gives voice to the Allied dead of World War One. His third and last stanza (it's a short poem) says majestically
Take up our quarrel with the foe:I can imagine the many Christian patriots who will not sleep (I know it's poor theology) and we "break faith" and live lives of non-involvement.
To you from failing hands we throw
The torch; be yours to hold it high.
If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders fields.
When Longfellow wrote his poem and admonished "listen my children, and you shall hear of the midnight ride of Paul Revere" he didn't tell us a key piece of American history, namely, that the good silversmith was galloping to the home of Pastor Jonas Clarke in Lexington. He know the patriot leaders John Hancock and Samuel Adams were lodging there, as they always did.
The next morning, on the lawn of Rev. Jonas Clarke's church, his congregation met the British and fired "the shot heard 'round the world."
Yep, our Independence started at a church, with a pastor and many of his congregation aiming muskets at an army of a tyrant.
Let us keep faith with them. There are many foes with whom we can quarrel. Let us do it now.