At last week's ways and means committee hearing on the Internal Revenue Service's treatment of tax-exempt organizations, Representative Aaron Schock (an Illinois Republican) helped propel a new firestorm across conservative media: in addition to tea party groups, Schock maintained, anti-abortion organizations were also being subjected to "horrible instances of IRS abuse of power, political and religious bias, and repression of their constitutional rights".

In one of the hearing's most charged moments, Schock interrogated the outgoing acting IRS Commissioner, Steven Miller, about how IRS personnel asked one of the groups to describe its public prayers. Senator Charles Grassley (an Iowa Republican) joined the fray during the Senate's finance committee hearings Tuesday.

For anyone who knows the history of the religious right, the possible revocation of tax-exempt status for claimed religious belief is a potent flashpoint. In his book, Thy Kingdom Come: An Evangelical's Lament, religion historian Randall Balmer argues that contrary to conventional wisdom, which Balmar calls the "abortion myth", evangelical voters were not propelled to political activism by the supreme court's 1973 decision in Roe v Wade.

Instead, the issue that mobilized these voters was the IRS's 1975 revocation of the tax-exempt status of the segregationist Bob Jones University. Rightwing religious architect Paul Weyrich told Balmer that it was "the federal government's moves against Christian schools" that actually "enraged the Christian community".

Bob Jones University claimed its ban on interracial dating and admission of students in interracial marriages was rooted in the Bible. It did not end its ban on interracial dating until 2000. The IRS's decision – which went through protracted litigation that ultimately ended when the supreme court let the revocation stand – was in response to new IRS regulations and a 1972 Supreme Court case holding that educational institutions with racially discriminatory policies were not entitled to tax exemption.

Balmar concluded:

"The Religious Right arose as a political movement for the purpose, effectively, of defending racial discrimination at Bob Jones University and at other segregated schools."

Denying tax-exempt status to racially discriminatory schools – regardless of whether they claim their religion commands it – is not the only issue which the IRS can lawfully examine an applicant's or organization's activities. Under IRS regulations, tax-exempt organizations "may not have purposes or activities that are illegal or violate fundamental public policy". The Bob Jones University case is just one example of the IRS applying this test. Its treatment of anti-abortion groups may be another.

Questioning anti-abortion groups – even the content of their prayers – could very likely have been aimed at determining whether these groups engaged in activities outside abortion clinics that ran afoul of the law. Because of the history of abortion clinic violence by those claiming a religious imperative, the IRS could have been attempting to determine whether the groups' activities were in violation of the Freedom of Access to Clinic Entrances Act (Face), a 1994 law which prohibits the use of force, the threat of force, or physical obstruction to injure, intimidate or interfere with someone's access to or provision of reproductive health services.

At last week's hearing, Schock entered a 150-page exhibit into the congressional record, a compilation of correspondence about tax-exempt status of three anti-abortion organizations. Two of them, Christian Voices for Life and Coalition for Life of Iowa, claim they were subjected to "unwarranted" questioning during the application process. A third, Small Victories, which already had tax-exempt status, claims to have been "harassed" and exposed to an "intrusive investigation". Christian Voices for Life and Coalition for Life of Iowa eventually obtained their tax-exempt status, and Small Victories' remained intact.

The exhibit was assembled by the groups' attorneys at the Thomas More Society, a rightwing law firm that defended anti-choice activists in National Organization for Women v Scheidler. The National Organization for Women (Now) brought that lawsuit aiming to put an end to clinic violence that had included: "invasions, violent blockades, arson, chemical attacks and bombings of women's health care clinics, assaults on patients, death threats and shootings of health care workers and administrators, including the murder of eight abortion providers."

Although Now's efforts to sue these protestors under federal racketeering laws was ultimately unsuccessful at the supreme court, the Thomas More Society still calls the litigation "a transparent attempt to gag pro-life activism at abortion clinics nationally".

The Face statute was enacted while this litigation was ongoing. It would not be unprecedented, for example, for an anti-choice activist to pray that an abortion provider die. While we still do not know what the IRS's thinking on this matter was, it is not entirely irrelevant or intrusive for the IRS to make such inquiries, including the nature of prayer.

Despite the hype and outrage about the Thomas More Society's clients' treatment by the IRS, the IRS ultimately did not penalize any of these organizations. But a religious right grudge against the IRS runs deep – back to its defense of Bob Jones University. It was just waiting to surface again.