In today's bracket, we have ecumenism up against inter-faith relations. These terms are often used interchangeably, as though they were synonyms. They are not the same thing. You could do both, but not with the same partner. An event could be both interfaith AND ecumenical, but it would need at least 3 participants.
Ecumenism is Christians working together. Since Vatican II (and before), there has been a desire for one Christian church, yet Christians often find more points of disagreement than agreement. While most (but not all) Christian churches are willing to participate in joint spiritual activities with other Christian churches, most continue to worship regularly, separately.
While, arguably, Christians should be able to unite under the cross for the sake of the world, it doesn't happen for a variety of reasons. I will offer myself as an example. I would be unwilling to join with the Roman Catholic Church and acknowledge the Pope as the head of the Church. That's a stumbling block to me. Yet I'm very glad to work with my Catholic brothers and sisters in ecumenical services. There are churches that will never permit the ordination of women. The fact of my ordination cannot be a fact to them since it is unacceptable. Yet they are willing, often, to put aside that issue so that we might work on a neighborhood service project or joint worship service.
Ecumenism is a struggle and a hope.
Inter-faith relations are exactly what they sound like. Relationships between people (or worship bodies) of different faiths. This could be relationships between organizations (a mosque and a church) or between people (a group of Methodists and a group of Mormons). Interfaith worship services can be touchy, because people either go ahead and acknowledge their differences (if a rabbi is praying, he/she is not going to do it in the name of Jesus) and let them stand or the organizers will try to make the service palatable to everyone and, thus, often meaningful to no one.
Inter-faith relationships are important because they increase understanding between groups. Faith families often have the power than states/governments lack to build relationships and develop communities.
The struggle in inter-faith relationships is how to take my faith seriously and respect yours. In my case, as a Christian, I have to take seriously Jesus' call in the Great Commission to go, baptize and teach all nations. If I take my faith seriously, then I do believe no one comes to God except through Christ. And I have to explain that to you, so that you might know the saving grace that is God's in Jesus.
Of course, the flipside is that the devout non-Christian sitting across from me is just as concerned about my soul as I, theirs. As much as we long to acknowledge one another faithfully, God calls us to be faithful first to the One who has been faithful to us. Even in acknowledging the God of Abraham, Isaac and Jacob, we're leaving out Ishmael.
[Positive] Inter-faith relations are a struggle and a hope.
So, if these came to a tourney, which would win? Well, I guess that depends on the nature of the competition. And who's playing.
Ultimately, I think they will go into sudden death overtime...
and God will win.