Maguet says the gist of opposition to unions is greed.

“A lot of employers just like to look at the bottom line. They think employees are making too much,” he says.

Then there is a common perception of unions as robber barons pillaging their own workers — a perception not without elements of truth in American history.

This past week the union-watchdog group Center for Union Facts launched a national ad campaign targeting labor leaders for turning their backs on the interests of employees.

The ads criticize labor leaders by alluding to instances of embezzling members’ dues, using the money to advance political agendas, and alienating workers through mismanagement of dues.

The ads’ verbiage includes words such as “corrupt” and “power-hungry” in their portrayal of union leaders.

The painted-with-broad-brush tone of the ads makes Maguet see red.

“That’s a bunch of hogwash. Yeah, there are isolated cases, but that’s true in any business,” Maguet says.

But union officials stress that Labor Day isn’t a time for strife but for an appreciation of the big picture of American workers’ contributions, and how the labor movement improved the lives of all workers.

“Labor Day isn’t a union/non-union issue. It’s a worker issue,” Marquardt says. “Unions represent all workers, and that’s what gets lost in the shuffle.”