Thursday’s U.S. Supreme Court ruling lets corporations, unions and interest groups spend on ads for or against candidates without making financial disclosures. Some corporations, including at least two in Louisiana, have decided to voluntarily report to the public their political expenditures nonetheless.

Well in advance of this week’s decision, the Center for Political Accountability had been pushing for corporations to adopt disclosure and board oversight rules to govern political spending. As of Thursday, the center listed 70 companies agreeing to the disclosures, 50 of which are on the influential S&P 100 index.

Companies operating or based in Louisiana who are on that list include Entergy and Chevron.

Both companies have lobbying arms, the Chevron Employees Political Action Committee and the Entergy Corporation Political Action Committee, that have been giving to candidates for years. Although  these companies now can  run ads attacking candidates who don’t reflect their agenda, or promoting those who do, they still cannot give money directly to candidates. To do that corporations always could and do rely on their PACs.

In the current race for Sen. David Vitter’s seat, the Chevron PAC has given $10,000 to the incumbent through 2009. The Entergy PAC gave $3,000 to Vitter. In the same year, the Chevron PAC gave $4,500 to Rep. Charles Melancon, who’s running against Vitter, while Entergy’s PAC has given him $10,000. Both candidates have raised roughly $655,000 from PACs.

Dissenting, Justice John Paul Stevens called the decision “radical” and a “departure from the common sense of the American people.” Longtime GOP lawyer Ben Ginsberg predicted to National Public Radio’s Nina Totenburg  that this election season would resemble “the wild, wild West.”

Although corporations still will be limited in how much they may directly give to a candidate, they can now spend freely on behalf of a candidate or cause. Under McCain-Feingold, corporations were prohibited from “electioneering communications” within 30 of a primary election and 60 days before a general. Those time restrictions are now gone.

It’s still unclear the extent to which disclosure requirements for third-party groups may be affected. Corporations previously had been reticent to funnel cash into third-party groups and trade associations such as the NRA or the Chamber of Commerce because those organizations had to disclose their donors. That will be the case now only when those organizations explicitly solicit contributions for political activities.

Lobbyist Lawrence Noble told The New York Times he would advise corporate clients that the threat of contributions being traced back to the company “is no longer a concern.”

The Supreme Court ruling also tossed out state and municipal campaign finance laws even more restrictive than McCain-Feingold. The implications of the decision could be most felt at the local level where a few wealthy individuals or corporations can more easily influence in an election.

For instance, here in Louisiana, political campaigns paid for by the oil and gas industry already urge local politicians to support their interests. Restrictions forced those ads to veil their language. That is why you might hear an advertisement paid for by a trade association urging you to “call State Senator X and tell her to vote against” some bill counter to their interests. Now, that veil is lifted. Oil companies can directly advocate for or against the election of a particular official. In states and localities dominated by one industry, it may be harder than ever for candidates favoring regulatory measures to get elected over a rival backed by companies capable of spending millions his or her behalf.

While campaign finance experts will need more time to sort out the implications, I’d be curious to know whether the Supreme Court’s decision would permit a mayoral hopefuls such as John Georges or Troy Henry from using the operating budgets of their private companies to finance ads on behalf of their own candidacies.

President Barack Obama immediately condemned the decision, as did both Sens. John McCain (R-Ariz.) and Russ Fiengold (D-Wisc.). It is likely that Congress will consider new legislation to re-regulate campaign finance. However many are pointing out that the Supreme Court’s broad ruling on the free speech rights of corporate entities will make it difficult to pass new, court-acceptable restrictions. With the major midterm elections coming this November, it will be interesting to see how quickly Congress is willing or able to act.

Most observers agreed that this ruling would help Republicans, who have traditionally supported industrial interests. But given the way corporate cash finds its way to sitting politicians who are voting on legislation that might affect an industry, it may help incumbents more than it does one particular party.