When the U.S. Supreme Court ruled in the 2010 Citizens United case that corporations, like people, are entitled to unimpeded free speech, it opened a new wild west frontier of political donations by corporations.

But not to worry, the court’s majority decision told some very worried citizens, disclosure rules applying to political action committees (PACs) will provide the sunshine you need to discover which candidates and policies the corporations are supporting.

The seven years since that ruling have demonstrated how little effect the light of disclosure can have against the looming shadow of dark money Super PACs that now dominate our politics.

But if the Republican Congress repeals the Johnson Amendment, as it is trying to do within it current tax reform legislation, the negative effects of Citizens United will seem mild by comparison.

Repeal would render meaningless the court’s assurances about the efficacy of disclosure and would allow big political spenders, including corporations, to not only hide their political donations from the public but also write them off as tax deductions. No, really.

Repeal, additionally, would seriously endanger the nation’s $400 billion private charity support system for the arts, education, science and hundreds of other good causes.

Ironically, the amendment oroginally was slipped into a 1954 tax reform bill by then-Sen. Lyndon Johnson (D-Texas) and adopted by the Republican congress without hearings or debate—much like the sorry course the current tax reform is on. It said that 501(c)3 groups — nonprofit charities, including churches — could not be involved directly in partisan politics such as endorsing candidates or parties. If they did, they would lose their tax-exempt status, meaning their donors could no longer deduct contributions, a death sentence for most charities.

As social issues such as abortion and same sex marriage became political hot buttons in the 1980s, some churches, frustrated that they risked their tax-exempt status if they became too openly political, sought relief. The GOP took up the cause of repealing the Johnson Amendment.

The nation’s private charity sector succeeds because the nonprofits are exempt from most taxes, contributors can write off their contributions and contributors’ names are kept confidential.

Imagine how quickly charities and churches of all sorts would be converted into de facto political parties — or competitor charities created out of whole cloth — if the nation’s biggest political spenders could launder their millions in a way that was, unlike their PAC contributions, both secret and tax deductible.

Imagine how much pressure legitimate charities would feel from politicians seeking their endorsements in return for contributions. That’s a distraction and conflict of interest most of them can’t afford and would not desire.

Imagine how many donors to, say, art museums would decide instead to give to more politically oriented nonprofits where they could get the same tax write-offs plus political clout.

So much for the court’s reassurances about disclosure. Repealing the Johnson Amendment would do three very bad things:

• Make dark political money even darker and harder to trace.

• Disrupt and eventually overwhelm a private charity system that has improved the country for decades.

• Put pressure on churches to become de facto political parties and fund-raisers, whether or not they consider partisan politics part of their spiritual mission. For instance, a large church being offered a secret, major gift if the pastor will endorse a specific candidate, party or issue.

Repeal would be another major blow to a political system already running half off the rails.

Davis Merritt, Wichita journalist and author, can be reached at dmerritt9@cox.net.