One of the most ambitious ideas yet proposed for a digital-era network-affiliate partnership is dead.

After more than five years of on-and-off discussions about a national-local cable news channel built of content from ABC News and ABC affiliates, the ABC Affiliate Association’s board of governors pulled the plug on any further talks.

The cause of death cited in a June 23 letter from board Chairman Ray Cole to ABC-affiliated stations and obtained by TelevisionWeek: “ABC recently informed the board that it would not honor its commitment for affiliate ownership.”

NBC and its affiliates share ownership in the NBC Weather Plus joint venture, but no other network has contemplated a joint news operation.

Content provided by the local stations was to be an essential element of the proposed channel, to be called ABC News Now. Therefore, ABC stations maintained from the start that it should be a joint venture, with the affiliate body and network both holding equity stakes and sharing control, an issue they regarded as just as important as a share of any revenues.

More than once over the course of the discussions, ABC and parent Walt Disney Co. had agreed to joint ownership, only to reverse position.

As recently as summer 2007, the affiliates felt both sides were on common ground again. The talks regained momentum, now focused on a channel designed to be carried on cable, rather than as a multicast adjunct to local broadcast stations as first envisioned by ABC News Network President David Westin. He had chafed at not having a 24-hour cable news channel such as NBC News has in MSNBC.

In October, Anne Sweeney, co-chair of Disney Media Networks and president of Disney-ABC Television Group, told TVNewsday Editor Harry A. Jessell that “pretty interesting conversations” about ABC News Now were ongoing.

Asked if a new cable network was in view, Ms. Sweeney said: “Knock on wood, yes.”

But in February, ABC affiliate representatives visiting Los Angeles were unsettled by hints that the network was rethinking its position. By May, all hard-won unanimity had unraveled, according to sources familiar with the history of the discussions.

Sources inside the network will say only that the affiliates’ desire for ownership was the problem.

Now the affiliates’ contract with ABC NewsOne, the clearinghouse/ exchange developed in the non-digital era for news content from local stations, will need to be negotiated anew. Because NewsOne was to have played a pivotal part in the joint venture, a new agreement was worked out as an addendum to the ABC News Now contract.

According to Mr. Cole’s letter, ABC now is proposing a more traditional option: that the affiliates participate without ownership in the cable version of ABC News Now that has evolved over the past four years from an Internet-only service to a multiplatform service carried by cable operators reaching some 30 million homes, in addition to mobile subscribers.

In his letter, Mr. Cole said the board does not endorse that option and is reviewing the rights of ABC to use any affiliates’ local content on any platform other than on the ABC broadcast network itself and on ABC-owned stations.

“The notion of ABC using ABC NewsOne content provided by local affiliates on competitive platforms was, of course, never originally contemplated by the NewsOne service,” Mr. Cole wrote.

Late last week, John Rouse, the senior VP of affiliate relations for the ABC Television Network, sent a short message of his own to affiliates.

“The ABC Television Network and members of the ABC board of governors spent much time and energy working together to explore a potential joint venture between ABC News and the ABC affiliates for a hybrid national/local news service. Those discussions have come to a close. Unfortunately, we were unable to find common ground on a business structure that would support each other’s interests,” he said.

He added that ABC News Now will continue in its current format.

“ABC will continue to discuss other opportunities to work together in new spaces, as we have with the ABC.com video player and most recently the ABC VOD initiative,” he said.

“This is a disappointing setback, especially in light of the great amount of time and other resources affiliates committed to the development of this project,” Mr. Cole, president-COO of Citadel Communications, told TelevisionWeek July 2. “But the affiliates and the network have demonstrated an ability to work together on other projects with great success over the past couple of years, and I’m confident that we’ll find additional opportunities where we will benefit from working together in the years ahead.”