Story highlights The provision could have led "dark money" contributions to become tax deductible

The rule change was in the House's version of the tax plan but not in the Senate's

(CNN) A controversial provision that would have permitted nonprofit groups to enter politics and could have led so-called "dark money" contributions to become tax deductible has been dropped from the GOP tax bill, according to a leading Senate Democrat.

Sen. Ron Wyden gave credit to his fellow Democrats for striking the Republican proposal to roll back the Johnson Amendment -- which prevents tax-exempt charities from directly participating in politics -- saying in a statement that they had stopped the measure "from being jammed into any final Republican tax deal."

"I will continue to fight all attempts to eliminate this critical provision that keeps the sanctity of our religious institutions intact, prevents the flow of dark money in politics, and keeps taxpayer dollars from advancing special interest biddings," the Oregon Democrat said in a statement.

The rule change was included in the House's version of the tax plan but not in the Senate's, leading to its inclusion in this week's reconciliation process.

While the House measure had restrictions in place to prevent direct campaign contributions, campaign finance experts contend that the regulations were vague and could have led to tax-deductible "sham" charities supporting candidates.

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