Unions at the crossroads.

By Stephen Franklin, Chicago Tribune Knight Ridder/Tribune Business News

Feb. 27--Leaders of the nation's 58 largest unions will gather in Las Vegas next week to talk about leadership, shrinking membership and ways to reinvigorate the AFL-CIO -- the organization that has linked and strengthened them for the last 50 years.

"Unity is our greatest asset, and we shouldn't do anything to undermine it," said AFL-CIO President John Sweeney, 70, who is seeking re-election.

But the Executive Council meeting he's walking into is not expected to be a model of harmony.

While the official agenda includes wide-ranging discussions on job losses, health care, minimum-wage fights with high-profile corporate giants like Wal-Mart Stores Inc., and the battle to prevent the privatization of Social Security, there will likely also be contentious discussion about Sweeney's leadership.

And whatever happens in Las Vegas won't stay there. It will set the stage for …