Church-State Organic Unity?

Vladimir Soloviev, in "The Russian Church and the Papacy", tells us that neither the Church nor the secular state (relying upon its own resources) can succeed in establishing "Christian justice and peace on earth."

In discussing the co-mingling of church and state, he says "if we consider the political and social condition of Europe toward the close of the Middle Ages, we must admit that the papacy, robbed of its secular organ... was unable to give a genuinely Christian organization to the society which it had governed."

He saw the social constitution of Europe as based on power disparity, an insurmountable barrier between "victors and vanquished". This caused a horrific tendency to do violence, making "every country the scene of civil war and plunder... Where in all this can the features of a truly Christian society be recognized?"

Turning to his modern era (late 19th century), Soloviev reviews secular efforts at providing political justice in Europe. Post-Reformation European states, freed from church oversight, tried to improve upon the Church's labor. The result?

"The philosophy of the revolutionaries has made praiseworthy attempts to substitute for [Christian] unity the unity of the human race--how successful is well known: a universal militarism transforming whole nations into hostile armies and itself inspired by a national hatred such as the Middle Ages never knew... and a continuous lessening of the moral power in individuals."

I am certain that had Soloviev lived to see the devastation of war upon Europe in the 20th century, his opinion would have only strengthened. This humanism-based unity continues in full force, but I am curious to know what will replace waning Nationalism (or will Nationalism resurge?). His individual moral power line was prophetic.

But I am not sure I can agree with the ultimate conclusion he reaches, that church and state must be closely aligned in an organic union "without confusion and without division (emphasis original)" to achieve "true social progress". My disagreement probably stems from my very non-Orthodox eschatological belief that such "true" progress is not for this world. The best I expect to see is fits of something less than "true" (i.e., idealistic, Kantian) progress, always to be interrupted by sin. Even granting that Christ gave His graces to the Church such that it can be preserved from all error, I don't see that flowing into an establishment of an infallible state. Heaven is not on earth. Not yet.