Fifty years ago, every Catholic church in Maine had at least one resident priest, parish lines were strictly enforced, the Mass was conducted in Latin, and the laity’s place was in the pews, not at the altar.

The implementation of Vatican II reforms in the mid-1960s began to change that. Masses could be celebrated in the language of the people and lay Catholics gained a greater role in the liturgy and parish governance.

Still, Maine’s shifting demographics and a critical shortage of priests in the Roman Catholic Diocese of Portland are expected to bring about dramatic changes in the way Catholics worship and administer their parishes.

So Bishop Richard Malone’s realignment, unveiled Tuesday, essentially abolishes traditional parish lines and calls on the laity to play a much bigger role in the life of the church.

The plan, to be implemented by 2010, reduces the number of clusters in the diocese from 31 to 27 and assigns a certain number of priests to each one.

Recommended by a committee dominated by laypeople, the plan offers four models for how the new clusters might structure themselves. They are:

. Multiple parishes merged into one with one staff, one pastoral council and multiple worship sites.

. Separate parishes with their own councils, but one staff and one cluster pastoral council and one finance council.

. One staff, merged parishes and a new, larger church building while closing older, smaller buildings.

. A combination of the above models.

Priests and lay leaders in the new clusters are to begin meeting in June with the assistance of Ernest Lebel, a human resources consultant based in Portland.

He will serve as the director of parish planning for evangelism, Malone announced Tuesday. Lebel, a Houlton native, served as the facilitator for the committee that drafted Tuesday’s plan.

Parishes in central Aroostook County have already been laying the groundwork for the implementation of the plan.

The Rev. Raymond Carey, a priest with the Roman Catholic Diocese of Seattle, conducted a Lenten retreat at Holy Rosary Catholic Church in Caribou that focused on preparing spiritually for the changes outlined Tuesday.

“A Chinese curse is, ‘May you have to undergo change soon,'” Carey told parishioners from churches in Presque Isle, Fort Fairfield and Limestone as well as Caribou who attended the February retreat.

Carey called on those attending to become “prophets” in the community.

“Prophets need to be able to face the pain that comes with change,” he said. “Prophets aren’t supposed to tell the future, they’re to speak the truth right now. … and have the long-term view at the same time.

“That is going to be essential to” the success of the plan, Carey said. “It cannot be just the voice of Bishop Malone and the priests. It cannot be just the voices of the perpetual ministers of the church. It’s got to be the voices of all God’s people.”

Malone said Tuesday that he is challenging people in the pews to play a larger role in the life of the church.

Malone added that he expects tensions and pain during the reorganization. The church, however, can either have “planned change” or let things unfold by themselves and face possible chaos down the road, he said.

“The church has not always been good at planned change,” Malone said. “But I think we’re taking hold of it in the Diocese of Portland.”