The controversy surrounding calls by British unions to boycott Israel is threatening to spill over into a major international union’s next election.

Leaders of some of America’s most powerful unions are said to be considering whether to pull support for a top British union official, Keith Sonnet, in his bid to lead a major international service workers union, Public Services International. The American union leaders are responding to last month’s passage of a resolution proposing a sweeping boycott of Israeli goods by Sonnet’s union, Unison, which represents 1.3 million public service workers.

The group that Sonnet is looking to lead, PSI, is a global federation of more than 600 unions from around the world, but the American labor movement has traditionally wielded significant power in its ranks.

As the number of British labor unions passing Israel boycott resolutions has snowballed in recent months, American trade union officials have raised alarms over the growing phenomenon, which encompasses boycotts of Israeli goods and academic institutions. Last week, nearly every top union leader in America signed on to a statement drafted by the Jewish Labor Committee decrying the raft of boycott proposals as non-constructive.

Avram Lyon, executive director of the JLC, said that Sonnet, who is running against Danish candidate Peter Waldorff for the international union post, had given assurances to American labor leaders in advance of his group’s national delegate conference that the Israel boycott measure up for consideration would either be voted down or have its teeth taken out. But the opposite came to pass, causing Sonnet’s American counterparts to feel misled, Lyon said.

“That has raised questions among some American unions as to whether or not they will support Keith Sonnet’s candidacy,” Lyon said. “The concern is based on the fact that Sonnet put forward a resolution which American unions would consider to be divisive.”...