All of my Left wing and evangelically atheistic friends who teach philosophy in Australia have severally as well as jointly declared today to be "Christian Left Appreciation Day". I also would like to say this much of a word of appreciation for fellow Christians who are on the Left. They bear a living witness to the fact that in Christ there is no Right or Left.
It is not the responsibility of the Church to dictate the specific politics of it's members. Each Christian is responsible to wise judge how the message of the church relates to their obligations as citizens in practice. It was the failure to distinguish between the mission of the church and the duties of citizenship that led to many forms of Constantinianism, including the social gospel movement.
This is not deny a fact of the matter about there being a "Christian Answer" to political issues, it rather puts the jurisdiction for finding that answer in the scope of the Christian citizen rather than in the ecclesial authority. Every Christian answers directly to God for their political judgements. Christians are called to pray and by implication adopt an attitude of good will toward the well being of the communities, cities, and states they find themselves in. It is up to them as to anyone else to decide how best to operationalize that good will.
Of course, respecting the total hardcoreness of this set of people, I charitably expect that by appreciating the Christian Left, they do not mean any Christian who is also left and would also agree with me about the distinction of spheres of church and citizen. What they would have on mind is the religious liberalism expressed by the "Social Gospel" which was not simply the combination of left wing causes with the ordinary historic proclamatory mission of the church, but the substitution of left wing (or right wing) causes for that historic mission. On this view, what Jesus commands when filtered through critical skeptical scholarship just is nothing but these causes. This eliminates the jurisdictional distinction by identifying the church with politics in leu of offering supernatural gifts. That would be more fitting for an evangelical atheist's "Christian Left Appreciation Day". But I admit for that I have no appreciation at all.