Not that Seraphim's reply needs anything added, but I have heard this statement far to many times:
"ecumenist" orthodox are in dialogue with other churches because we want to subvert the process and introduce them to Orthodoxy, not because we want to join some amorphous "future church."
A few think that these dialogs, meetings, treaties, joint decrees, services, and speeches of those new-calendar "churches" is not taking place for the purpose of union, but for the purpose of enlightenment and mission to the heterodox. "These are", they say, "manifestations of love for our brothers". "If we shut ourselves in our shell", they often say, "if we do not attend the international conferences and send observers to the Papal synods, etc., then how will the Westerners know the Orthodox Church, and how will they be attracted towards her?"
But how will the heretics be taught that the Orthodox Church is the One and True Church when they see her consorting with the false "churches" as an equal among equals? Will they not think, therefore, that Orthodoxy is also like the others - relative and partial? Or is it reasonable for one to hope that those councils of fanatic biretta-wearers, toga-taughting muftis, and homosexual pastors will ever be able to recognize the truth? They are only flattering the Orthodox for the sake of their own motives. If they had a genuine nostalgia to know Orthodoxy, they would have no need for councils and conferences. They would have gone to drink from her sources, from her Fathers and Saints.
No! the best way to convince others of the truth is to believe in it yourself. Do not discuss it, only confess it. Sure, people may not like you and the conversation may be short, and so be it. Councils and conferences debate the truth. But this is a betrayal, because in such instances it is not a matter of dialogue with and admonition to heretics, but of discussion with "churches". Christ does not ask for debaters, but for confessors. The truth which He taught us is not the kind that is debatable. In the various ecumenical conferences the discussion takes the form of commerce, where an exchange of compromises takes place in matters of faith in order to arrive at a final agreement. Under such conditions even the mere attendance of an Orthodox at an ecumenical conference is a betrayal of Christ. It is the betrayal of Christ to unbelievers for thirty pieces of silver, because by attending, the Orthodox admits his Faith to be debatable, and permits the notion that he too will make compromises if he is given a satisfactory exchange.
If, instead of this, all those who speak of union today would confess Orthodoxy as the only and absolute truth and refuse every official and unofficial ecclesiastical contact with heretics, without fearing to name them as such, then their voice would be heard much farther; and more important, it would be respected and would provoke thought. Whereas now their voice is a voice of compromises, a voice which does not move anyone, a voice which, deep down, no one respects.
The Fathers did not enter into discussions with heretics. They confessed the truth and refuted their claims without courteousness and compliments. They never arrived at mutual understandings with heretical "churches". Their dialogue was always public and had a view to the salvation and edification of souls. The Orthodox Church did not converse with "churches" of the heretics. It was not a discussion of the Church with churches, but a dialogue between the Church and souls who had lost their way. The Church does not discuss, for she does not seek. She simply gives - because she has everything.
But don't be fooled into believing this lie of theirs, that they are on a mission to the heterodox, this is the smoke screen they have erected in order to quiet the conscience of people who only need an ecxuse to put their mind at rest, so they don't have to be provoked into action. They want to believe this lie, they just need the lie to beleive.
And it is true, that the ecumenist church is not nessesarily endeavoring or some official union. For those who would whiff this poison of theirs - syncretism, clearly the message is that Christ is a great mystic, a great philosopher, a great moral teacher, perhaps even a god, but under no circumstances the God. He is a way, but not the Way. He is a truth, but not the Truth. He is a light, but not the Light. Orthodoxy is a path, but not the Path. Other paths exist that are equally good. Yes, a homogenization of religions is not about to take place. Let everyone hold to his own way. All that is required is that he not be a fanatic; that he not think that Orthodoxy is the only religion that exists in the world and none else; that he not think that only Orthodox bishops are bishops, and that heretics are nothing; that he no longer think that only in Christ can one know God, and that so many millions of Hebrews, Moslems, Buddhists, etc., are far from God.
This is the heresy that we are struggling with, and not some sort of union that has not as yet taken place. This heresy is the denial of Christ and His Holy Church.
EDIT: I also want to add, that in the days when Christians were under Roman persecution, everyone was required to pay homage to the Roman gods; a man would issue a certificate that the tribute was paid, and with this certificate, you would be safe.
In those days one would only have to bribe the person to get a certificate without offering incense or any other tribute. But those Christians would not do this, because they considered that even this was a denial of our Lord and Savior. So they went to be martyred! Today, not only is the ecumenist church willing to go pray with the muftis and honor their gods, but for much less a cause.