The Internal Revenue Service has failed to turn over documents requested by the powerful Senate tax-writing panel, which is investigating the tax agency´s practice of targeting conservative organizations. Senate Finance Committee Chairman Max Baucus, D-Mont., and Sen. Orrin Hatch of Utah, the panel´s top Republican, gave the IRS a May 31 deadline to answer dozens of questions related to the special scrutiny the agency was giving to right-leaning groups seeking tax-exempt status. But the troubled IRS let the deadline go by.