Internal Revenue Service officials have invoked a Watergate-era law designed to protect private citizens’ tax returns to justify their refusal to turn over documents requested by the House Ways and Means Committee.

In its first official response to a May 14 bipartisan request from the committee for information and documents related to the agency’s illegal harassment of conservative, evangelical and pro-Israel groups, the IRS told lawmakers on June 4 that Section 6103 of the federal tax code allows it to exempt itself from compliance with such congressional requests.