Former Rhode Island state Sen. John Celona has been sentenced to prison for using his public office to serve the interests of businesses that hired him. Why shouldn’t legislators who do the bidding of unions that hired them be treated exactly the same way?

Unions, after all, are effectively very big businesses. Indeed, they are one of the most powerful economic interests in Rhode Island politics.

That’s why it’s encouraging that state Rep. Douglas Gablinske (D.-Bristol), a small-business owner, is urging the state Ethics Commission to make the rules apply to all. As the U.S. attorney’s office investigates apparently extensive corruption on Smith Hill, lawmakers from both parties should join with him.

Mr. Gablinske says the commission should make it clear, on behalf of cleaner Rhode Island government, that legislators who are hired specifically by unions should be bound by conflict-of-interest laws.

Several legislators get big salaries from public-employee unions who have a huge and direct financial interest in the actions they undertake in the State House — unlike mere members of unions, who are not as directly dependent on unions for money. Sen. John Tassoni (D.-Smithfield) is the $88,549-a-year business agent of Rhode Island Council 94, American Federation of State, County and Municipal Employees (AFSCME). Senate Majority Whip Dominick Ruggerio (D.-North Providence) receives $176,070 in “salary/benefits” per year from the New England Laborers’ Labor-Management Corporation Trust. Branches of the Laborers’ union also employ Senators Paul Moura (D.-East Providence) and Frank Ciccone (D.-Providence). (Those branches declined to report their hired legislators’ salaries.)

It is extraordinary that the Ethics Commission has ignored this glaring conflict for so long. “Sometimes unnatural things become natural because they go on for so long,” Mr. Gablinske noted. “The conflict is as obvious as the nose on your face.”

It’s not easy for the freshman representative to be outspoken on this matter. Several of his colleagues get a lot of money working for the unions, and unions in the past have backed primary challengers against lawmakers who fail to sufficiently serve their wishes.

But, as he says: “I was elected to go up there to do a job. I wasn’t elected to go up there and make friends.” As the Feds’ growing investigation into corruption on Smith Hill suggests, we need more legislators who think that way.