There may be no bigger political target and punching bag than the Internal Revenue Service, and that is obvious on this Monday, as Republicans express outrage over reports that the IRS had targeted more conservative political groups for review of their tax-exempt status applications, and even a few Democrats joined in as well.

Sen. Marco Rubio (R-FL) became the first well known lawmaker to call for heads to roll, using a letter to the Treasury Secretary to demand the ouster of the IRS Commissioner Steven Miller (who happens to be serving in that post in an "Acting" role).  Here is the letter Rubio sent:

May 13, 2013

The Honorable Jack Lew

Secretary

U.S. Department of the Treasury

1500 Pennsylvania Avenue, NW

Washington, D.C. 20220

Dear Secretary Lew:

Recent revelations about the Internal Revenue Service's selective and deliberate targeting of conservative organizations are outrageous and seriously concerning. This years-long abuse of government power is an assault on the free speech rights of all Americans. This direct assault on our Constitution further justifies the American people's distrust in government and its ability to properly implement our laws.

The American people deserve answers about how such seemingly unconstitutional and potentially criminal behavior could occur, and who else was aware of it throughout the Administration. It is imperative that you, your predecessor, and other past and present high-ranking officials at the Department of Treasury and IRS immediately testify before Congress.

The public expects your complete cooperation with both congressional investigations and potential criminal inquiries. If investigations reveal that bureaucrats or political appointees engaged in unconstitutional or criminal targeting of conservative taxpayers, they must be prosecuted to the fullest extent of the law. At a bare minimum, those involved with this deeply offensive use of government power have committed a violation of the public trust that has already had a profoundly chilling effect on free speech. Such behavior cannot be excused with a simple apology.

Furthermore, it is clear the IRS cannot operate with even a shred of the American people's confidence under the current leadership. Therefore, I strongly urge that you and President Obama demand the IRS Commissioner's resignation, effectively immediately. No government agency that has behaved in such a manner can possibly instill any faith and respect from the American public.

Sincerely,

Marco Rubio

Meanwhile, Rep. Mike Turner (R-OH), introduced a bill that would toughen penalties allowed against IRS employees for unfairly targeting certain people or groups in the administration of IRS laws.

"Americans of all political beliefs have been rightly outraged by the revelation of the IRS’ efforts to target certain political organizations," Turner said in a statement.  "The fact that this could occur with little to no corrective action against those who seek to silence their fellow citizens is unacceptable."

You can see a copy of Turner's bill here.

As for Democrats, a few of them began speaking up in the morning, though they were still far outnumbered by GOP lawmakers.

"There's no excuse for ideological discrimination in our system," said Sen. Tim Kaine (D-VA), who noted that one of the groups given an extra look by the IRS was from his home state.

But clearly, there was much more interest on the GOP side.

"The IRS's gross abuse of power would have our founding fathers rolling in their graves," said Rep. Vern Buchanan (R-FL).

The controversy was also noticed by those out of power as well.

"Although the IRS claims this was an honest mistake, these revelations are troubling on many levels," wrote two officials of the ACLU, raising questions about IRS plans to force political groups to disclose the identities of their donors.