Ecumenism is the effort of the Church to build bridges of dialogue between other religions and itself.
It is not a plan to establish a single, lowest-common-denominator religion where doctrines and disciplines are diluted and compromised so that anyone and everyone can fit in. Ecumenism acknowledges the historical realities of mistakes and abuses made by individuals within the church and the disunity which now exists, especially among the numerous Christian denominations.
Catholic ecumenism does not try to impose unity, nor does it pretend complete unity exists. Ecumenical work seeks to heal old wounds of division, but not by altering doctrine. It seeks cooperation and mutual respect wherever possible.
Charitable works of mercy have been jointly done by Catholic charities and Lutheran social services, for example. Thanksgiving prayer services have been held across America where Protestants, Catholics, Jews, Muslims, and others gather and express gratitude for the blessings God has sent to our nation.
Ecumenism seeks to avoid name-calling, and rather than presenting doctrines in an either-or context, tries to show that Catholicism firmly believes she has the fullness of truth and grace, but that other churches also have some truth and some grace. So, it is no longer “We’re right, and you’re wrong;” rather, it is “We have the full and complete story.”
Since the Eastern Orthodox Church has valid sacraments, the efforts of reunifying them with the Latin Roman Catholic Church were a high priority to Pope John Paul the Great and now to Pope Benedict XVI as well. Union with Protestants is more problematic due to the enormous and significant differences of doctrine, discipline, and worship.
Yet popes and councils have never stopped making efforts to work together as fellow Christians to feed the poor, minister to the sick, and work for peace.