Christian pastors reportedly are defying IRS rules and endorsing political candidates at an unprecedented rate.

Under IRS rules, nonprofits -- such as churches -- are allowed to discuss politically sensitive subjects in their sermons, but historically have been barred from actively campaigning and endorsing particular candidates. But a growing number of pastors are challenging that standard – and the IRS may be looking the other way.

Politico reports that, according to the group Alliance Defending Freedom, more than 1,600 pastors are endorsing candidates this year as part of so-called Pulpit Freedom Sunday.

That’s up from a mere 33 pastors in 2008. Alliance Defending Freedom is urging pastors across the country to endorse candidates on any Sunday leading up to Election Day.

The pastors reportedly have weighed in on tight races ranging from the North Carolina Senate battle to the brawl between Senate GOP Leader Mitch McConnell and Democrat Alison Lundergan Grimes in Kentucky.

The IRS previously has been sued for not enforcing their endorsement ban for churches, leading to a recent settlement. The argument against pastors making endorsements is that they are using tax-exempt money for political purposes.

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However, the IRS may be gun-shy after its high-profile fight with Tea Party groups and virtually all Republicans on Capitol Hill over its targeting of conservative groups.

IRS Commissioner John Koskinen recently suggested the IRS was not going to crank up enforcement on churches, despite the settlement.