WASHINGTON - Bob Casey wanted more contrition. Bob Menendez wanted scrutiny of what he called "a second scandal." And Pat Toomey wanted to know how anyone could see IRS targeting of conservatives as anything but political.

"On the face of it, it certainly appears that it is completely politically motivated," Toomey (R., Pa.) said at a Senate hearing Tuesday, challenging explanations put forward by the agency's leaders. "To the best of my knowledge, there was no criteria identifying left-of-center organizations as deserving special scrutiny."

The three Philadelphia-area senators on the Finance Committee took turns questioning and criticizing (mostly criticizing) the current and former heads of the IRS at the committee's hearing looking into the agency's heavy-handed examinations of tea party groups.

The region's lawmakers all registered their outrage and, like other panel members, tried to shape the continuing debate over the agency's actions.

IRS officials argued that the agency did not set out with political aims, though it singled out right-leaning organizations seeking tax-exempt status.

"What happened here was that foolish mistakes were made by people trying" to handle workloads more efficiently, said Steven Miller, the acting IRS commissioner, who last week was pressured to step down in June. While the targeting was "intolerable," he said, it was a "mistake and not an act of partisanship."

Toomey questioned how Miller could reach that conclusion. He pointed to IRS leaders' inability - or unwillingness - to say who allowed tea party groups to be targeted again after the added scrutiny had initially been stopped.

"We don't even know who made the decision. How do we know what motivated that decision?" Toomey asked.

"It's frustrating to have no answers for a hearing like this," he said.

Casey (D., Pa.) was angered by what he saw as a lack of contrition on the part of Miller and Douglas Shulman, the former IRS commissioner who oversaw the agency while some of the added scrutiny occurred.

"I wish there was more of a sense of, frankly, of outrage, or at least more contrition being demonstrated," Casey told the two. He said he expected "at a minimum a sense of disappointment and contrition as opposed to 'We didn't know' and, I think, an attitude that only makes the problem worse."

Miller had opened his testimony with an apology and later said he took responsibility for any IRS actions under his watch.

Menendez (D., N.J.) called the singling-out of conservative groups "truly offensive to our concept of democracy" and "pretty appalling." He said it undermined citizens' faith that government "will work in a way that is fair and transparent."

But Menendez also said there was another scandal.

The other one, he argued, is the way tax exemptions are given to groups that are labeled "social welfare organizations" but have clear political aims.

He singled out Republican strategist Karl Rove's political group Crossroads GPS, while saying there were others on both sides of the political spectrum who did the same thing.

"There is a reason that you seek a 501(c)(4) status - because you can hide your donors and you also have a tax advantage," Menendez said, referring to the section of the tax code that permits such exemptions. "I'd like to see what does it cost the American taxpayers in the granting of all of these 501(c)(4)s when they are not being used for social welfare but they are being used in essence for political advocacy."

Toomey pushed back on that idea later in the hearing, citing American history to defend the concept of letting some political groups keep their donors anonymous. Other types of political action organizations have to say who funds them.

"Perhaps one of the most important and influential works of political advocacy ever done in the history of the republic were the Federalist Papers," Toomey said, "which were written anonymously, under pseudonyms."