Less than two weeks since taking over as the acting commissioner at the Internal Revenue Service, Daniel Werfel admonished the agency's culture of mismanagement for the missteps that have blanketed the IRS in controversy and created an appearance of partisanship.

"It's completely inexcusable, and it's inherently damaging," Werfel said, during his first appearance on Capitol Hill in his new capacity. "We failed in that most basic core principle [impartiality] here."

Rep. Ander Crenshaw, R-Fla., the chairman of the Financial Services and General Government Subcommittee of the House Appropriations Committee, said that "before Congress spends one more dime on the IRS, we need to know how it spends the money it already receives" and "what safeguards the IRS plans to have in place to make sure the funds are used in a legal and appropriate way."

"Targeting groups based on their names and political beliefs is both chilling and outrageous," Crenshaw said. "It's time to talk about what happened, how it happened, who came up with this plan and why, how widespread were these abuses, who was responsible, who's going to be held accountable and how do we make sure this never happens again."

Werfel, who was appointed by President Obama to replace the previous acting commissioner, Steven Miller, on May 16, pledged to restore the agency's reputation as an independent, impartial agency.

"There was a fundamental failure by IRS management to prevent this inconsistent treatment and ensure that it was halted once management became aware. These failures have undermined the public's trust in the IRS's ability to administer the tax laws in a fair and impartial manner, and they must be corrected," Werfel testified. "The agency stands ready to confront the problems that occurred, hold accountable those who acted inappropriately, be open about what happened and permanently fix these problems, so that such missteps do not occur again."

Rep. Harold Rogers, R-Ky., the chairman of the full Appropriations committee, suggested tying any future appropriations to the IRS's ability to implement the inspector general's recommendations.

"We may want to consider putting conditions on your funding that allow us to monitor your agency's compliance with proper practices. This committee has done that before, and we very well may be in that mode again," Rogers said. "I don't need to remind you or anyone else that the power of the purse rests in the Congress, and we're prepared to use that purse to get to the truth."

J. Russell George, the inspector general whose report first revealed the extent of the targeting, suggested that tying future appropriations to results was a reasonable suggestion, in addition to regular reports to the committees of jurisdiction and oversight responsibilities of the inspector general's office.

"The IRS still has work to do to resolve these troubling allegations and to ensure that they do not happen again," George said. "We plan to conduct additional audits to assist the IRS' progress in addressing our recommendations."

Tuesday representatives from several organizations that faced excessive scrutiny in their applications for tax-exempt status will testify before the House Ways and Means Committee.

Among the witnesses: John Eastman, chairman, National Organization for Marriage; Diane Besom, Laurens County Tea Party; Becky Gerritson, Wetumpka Tea Party; Karen Kenny, San Fernando Valley Patriots; Kevin Kookogey, founder and president, Linchpins of Liberty; and Sue Martinek, Coalition for Life of Iowa.