A union challenge to the state’s right-to-work law was definitely expected. The challenge that has been offered, however, lacks in credibility, according to this excerpted editorial that first appeared in the Lafayette Journal & Courier and has been echoed in other circles.

In a federal lawsuit filed in federal court, attorneys for the International Union of Operating Engineers Local 150 argue that the right-to-work law infringes on the unions’ freedom of speech.

How? The right-to-work law, signed into law this year, allows workers to skip paying union dues even if the union bargains for wages and benefits on their behalf. The lawsuit’s contention is that right-to-work limits a union’s ability to build up coffers needed to negotiate beyond the plant floor — namely in Statehouses and other political lobbying settings.

The brief filed last month, according to an Associated Press account, cites the U.S. Supreme Court’s Citizens United ruling, which made corporate campaign spending free from many reporting restrictions. Nice try.

The unions, which are scheduled to get a hearing in federal court later this month, are already being called on the strategy by legal experts. And rightly so. The Citizens United decision, whether rightly or wrongly sorted out by the U.S. Supreme Court, was about spending money to boost political speech without many of the past reporting restrictions. It was not about how corporations or organizations raised that money.

Unions faced those potential fundraising limitations before right to work, with union members able to opt out of dues that were beyond those needed for negotiations.

If unions are serious about bringing down Indiana’s right-to-work law, we’re guessing they’ll have to try another approach.