The influence of "dark money" on Alabama state politics has emerged as a key issue in light of the scandal currently roiling Gov. Robert Bentley's administration.

In November, the Center for Public Integrity gave Alabama an "F" grade for its laws on political financing. Only eight states ranked below Alabama.

That dubious rating came as a result of loopholes in state law including inadequate limits on donations to candidates and political parties and the state's persistent inability or unwillingness to investigate and impose sanctions on those who break campaign finance rules.

Those shortfalls combine with a lack of meaningful restrictions on dark money - a term used to describe certain political spending that does not require the disclosure of donors - to create powerful influences on state elections and politicians.

"The most obvious way [dark money] influences elections is by keeping people from getting the information they need. To make intelligent decisions, they need to know who's funding their elections," Richard Skinner, a policy analyst at the Washington, D.C.-based Sunlight Foundation, told AL.com.

"That's really the most fundamental thing. We don't know what's prompting the spending, what kinds of interests are behind it."

One of the outgrowths of Citizens United and other recent U.S. Supreme Court rulings in favor of more political speech, dark money typically refers to spending by politically active nonprofits that claim 501(c)(4) or 501(c)(6) tax status. In order to qualify as a 501(c)(4), "an organization must not be organized for profit and must be operated exclusively to promote social welfare," according to the IRS.

But many dark money groups remain cloaked in secrecy, able to wield great influence despite the restrictions.

During his 2014 reelection campaign, Bentley refused to accept funds from a political action committee associated with dark money, citing transparency concerns. But his former top political adviser, Rebekah Caldwell Mason - with whom Bentley allegedly had an affair, according to his former top law enforcement official, Spencer Collier - was paid by one such group after he was elected.

There are fledgling attempts to reign in dark money's influence on Alabama politics. One such effort is a bill introduced last month by Sen. Arthur Orr, a Republican from Decatur, that would establish stronger state constitutional footing for the Legislature to pass laws aimed at changing the way the campaign finance system operates.

But critics worry about dark money's influence on elections, which has only grown in recent years.

"[S]pending by organizations that do not disclose their donors has increased from less than $5.2 million in 2006 to well over $300 million in the 2012 presidential cycle and more than $174 million in the 2014 midterms," the Center for Responsive Politics reported.

Many observers say that the lack of viable mechanisms for regulating 501(c)(4)s leaves too much wiggle room for groups to make their mark on policy and elections without disclosing their donors.

"Expenditures [during] a campaign can have impacts on voting outcomes, which is one of those things these groups are trying to do. Additionally, even if it doesn't impact an election outcome, it might have an impact on how the elected candidate governs," Pete Quist, research director at the Montana-based National Institute on Money in State Politics, told AL.com.

"The idea of why they're donating comes into question there. Usually they're supporting someone whose ideals are in alignment with theirs."