Campaign contributions are like the rising tide.

Whatever barriers or legal restrictions you put in the way, the cash, like the rising sea, will find its way around them. You plug one hole, the money finds another route, another way around.

That, sadly, is the story of campaign-finance reform in New Jersey and elsewhere.

The good news: The state sent a powerful message last week with the criminal indictment of seven current and former executives of Birdsall Services Group, one of the state's largest engineering firms. The Birdsall executives - who are charged with conspiracy, money-laundering, making false representations for government contracts and a number of lesser charges - face prison terms of as long as 10 to 20 years.

State pay-to-play laws prohibit companies with government contracts worth $17,500 or more from making political contributions of more than $300. Birdsall received $28 million in government contracts in 2011 (and $86.7 million in contracts since 2008).

But according to the state Attorney General's Office, the Birdsall executives skirted the pay-to-play law by soliciting personal contributions of $300 from employees, bundling those checks together and sending them to campaigns and political organizations. The employees were then illegally reimbursed through bonus payments, according to the state.

The charges allege that the scheme went on for six years and resulted in $686,000 in contributions - to Democrats and Republicans - that should have disqualified Birdsall from obtaining the government contracts.

Think about the depth of this alleged deception: The Birdsall executives had to know they were breaking the law. Their employees had to know their individual contributions of $300 were being used to circumvent the law. And most shamefully of all, the campaigns and political organizations cashing all these $300 checks had to know what was going on.

The Attorney General's Office, saying the investigation is ongoing, did not name the elected officials who received the money, but the indictment does say the alleged crimes took place in Ocean, Monmouth, Mercer, Middlesex and Bergen counties.

No doubt the alleged scheme paid off for the Eatontown-based Birdsall in the form of lucrative engineering contracts from government entities. Contributions from professionals such as lawyers and engineers, who can be awarded contracts without public bidding, have long been at the center of the pay-to-play problem.

As former state Sen. Bill Schluter told The Star-Ledger, "They know where the money is going, where the money is from and what it's for. They don't have to have a quid pro quo. It's a wink and a nod."

But now some Birdsall big shots are looking at prison time. That should scare a lot of people in New Jersey, because we promise you - Birdsall isn't the only company playing this game.