Whether any of the church's nearly $8 billion portfolio will ever be pulled from companies doing business in the West Bank or related areas is a long way from being determined. The process, however, is slowly moving forward.
Israel's occupation "is at the centre of the cycle of violence in the region - whether it is suicide bombings or the displacement caused by the occupation ... and impedes a peaceful solution to that conflict," said the committee now picking out possible divestment targets.
The church's General Assembly which set the matter in motion in July called for a "phased, selective divestment" beginning no earlier than July 2006, the next time the governing body meets. One dissident group, however, wants a moratorium placed on the whole project now and is asking the church's interim leadership to do so as early as next month.
No companies have yet been singled out, but a report identifying which firms might "most usefully be engaged" by the threat of divestment is due to be issued in August, the investment review committee said.
Caterpillar Inc has long been linked to the issue. Last November Human Rights Watch urged it to stop selling bulldozers to the Israeli army, saying they were used to demolish Palestinian homes in Gaza and the West Bank that posed no security threat.
The investment committee said it is looking at reports from the Sisters of Loretto and Jewish Voice for Peace who have filed a shareholders' resolution with Caterpillar. The resolution questions whether sale of equipment to Israel complies with the company's world-wide code of business conduct.
Caterpillar's response has been that it has neither the right nor the ability to monitor what happens to its products once sold.
No one knows yet how much of the church's portfolio - investments covering pensions and other holdings controlled by the church leadership - might be at issue or which companies would be approached.
The Reverend William Somplatsky-Jarman, speaking for the investment committee, said the matter is "a slow, deliberate process ... with actual divestment being a last resort." The goal is not "divestment for divestment's sake," he said, "but rather to use dialogue, shareholder resolutions and public pressure to persuade corporations to change business practices that inflict harm on the innocent."
The process has already fractured the church, whose membership covers the bulk of US Presbyterian faithful. The next three largest Presbyterian groups have fewer than 400,000 members.
"The General Assembly made a very important, very political, very visible statement on behalf of the church that does not enjoy the overall support of its members and has very deeply divided both the church and the Jewish and Presbyterian communities," said Valerie Munson of Philadelphia, who helped organise Presbyterians Concerned for Jewish and Christian Relations.
The opponents hope to present a petition urging the church to drop the idea to the leadership next month.
Added the Reverend William Harter of Chambersburg, Pennsylvania, who formed the group along with Munson: "We'd like it stopped beforehand because of the uproar it has created in the church."
The proposal amounts to a "one-sided tilt" putting pressure on Israel when the situation is far more complex, he added. A key point, he said, is that the dissent is coming from within the church and not in response to Jewish interests, which are clearly upset.
"Instead of talking about peace we're talking about Presbyterians," said David Elcott, director of inter-religious affairs for the American Jewish Committee. "They have deflected conversation in a very negative way."
The problem, he said, is that the proposal is rolling at a time of "Palestinian moves for accommodation and reconciliation with Israel" and renewed US efforts to bring peace to the region. "They are," Elcott said, "on the ironic side of being on the wrong side of the divide here."
The Reverend Mathame Sanders, a missionary now posted to the church's headquarters in Kentucky who served in the West Bank, said the proposal gives "us the opportunity to talk about what has been consistent in the (church's) statements since 1948: Two states for Israelis and Palestinians in security and dignity."
So far the divestment idea has not caught on elsewhere in the United States, where there are an estimated 161 million Christian church members.
Nor would rank-and-pew Presbyterians who disagree have much power to reverse it unless they can get next year's General Assembly meeting to withdraw or delay it.