The Internal Revenue Service on Thursday abandoned its effort to force five big-ticket donors to pay gift taxes on contributions they made to nonprofit advocacy groups that are playing an increasing role in American politics.
“Until further notice, examination resources should not be expended on this issue,” Steven T. Miller, deputy commissioner for services and enforcement, wrote in a memo posted on the I.R.S. Web site.
“This is a difficult area,” Mr. Miller wrote, “with significant legal, administrative and policy implications with respect to which we have little enforcement history.”
The memo was a sharp reversal for the tax agency, which had invoked a rarely used, 30-year-old ruling to warn the five donors in February that they might owe gift taxes on their donations. Organizations heavily financed by conservative donors like David Koch, or in the case of Crossroads GPS, tied to top Republican strategists like Karl Rove, would have come under such newly enforced rules, were they to be imposed across the board.