Many like to write about the mainline's decline over the last fifty years, though plenty of evidence now suggest that it is not limited to the mainline and that the picture is far more complex than often presented, but historian David Hollinger speaks about the incredible achievements of the Mainline during that time:
The ecumenical leaders achieved much more than they and their successors give them credit for. They led millions of American Protestants in directions demanded by the changing circumstances of the times and by their own theological tradition. These ecumenical leaders took a series of risks, asking their constituency to follow them in antiracist, anti-imperialist, feminist and multicultural directions that were understandably resisted by large segments of the white public, especially in the Protestant-intensive southern states.
It is true that the so-called mainstream lost numbers to churches that stood apart from or even opposed these initiatives, and ecumenical leaders simultaneously failed to persuade many of their own progeny that churches remained essential institutions in the advancement of these values.
But the fact remains that the public life of the United States moved farther in the directions advocated in 1960 by the Christian Century than in the directions then advocated by Christianity Today. It might be hyperbolic to say that ecumenists experienced a cultural victory and an organizational defeat, but there is something to that view. Ecumenists yielded much of the symbolic capital of Christianity to evangelicals, which is a significant loss. But ecumenists won much of the U.S. There are trade-offs.