You would have thought, at this point, that everyone understood that it is not only wrong, but politically hazardous, to use the IRS to target groups or individuals based on their politics. Richard Nixon met his political end, in part, because of misuse of the Internal Revenue Service.

Yet, now, it turns out the IRS has taken a special interest in the finances of groups associated with the conservative tea party or with words such as “patriot” in their names. Such targeting is as shocking as it is stupid. The action certainly violated agency rules and was quite possibly illegal.

It seems certain that this was not merely some low-level operation. No renegade auditor decided on his own to take on the tea party. Indeed, according to the Washington Post, documents it obtained show that the IRS office responsible for evaluating applications for tax-exempt status decided to focus on groups making statements that “criticize how the country is being run” and those that were involved in educating Americans “on the Constitution and Bill of Rights.”

Sen. Susan Collins, a moderate Republican from Maine, called the revelation “absolutely chilling,” which it clearly is. If the policy doesn’t amount to using the vast power of the IRS to punish political opponents, then it certainly looks like it. Congressional investigations are warranted, and on the way.

The IRS apologized on Friday. On Monday, President Obama denounced the program as outrageous and demanded that those responsible be held accountable. On Tuesday, Justice opened up a criminal investigation.

That’s a start, but given the nature of the offense and the nation’s fractured politics, it is all but certain that an effort will be made to see how close to the Oval Office the decision to target conservatives reached.

The investigations need to go forward, one hopes with a minimum of political theater and with maximum value placed on finding out exactly what happened.

No doubt, Republicans will make political hay out of this, extending their investigations well into the 2014 election season, just as Democrats would if their roles were reversed. But there is a larger issue at stake here, one that everyone, including the president, seems to recognize. That is the issue that Congress needs to focus on.

None of this, of course, prevents Obama from getting to the bottom of the AP phone records or IRS matters on his own. It’s his administration that has been caught in indefensible acts. It is his responsibility, and it is in his interest, to move quickly.