whitehouse replacing U.S. attorneys

I recently wrote "impeachment should be reserved for the most serious of cases, those that interfere with the voters' abilities to oversee the President." I'm leery of impeachment. I think it's been misused for political purposes, such as in Clinton's case, and that recalling politicians like that tends to destabilize the federal government, which isn't set up to be a parliamentary system. However, I may have to expand what I'd consider an impeachable offense.

Talking Points Memo is carrying a story on the Bush administration replacing U.S. attorneys who are involved in investigating political corruption:

Okay, so we already know that the White House has now taken the unprecedented step of firing at least four and likely seven US Attorneys in the middle of their terms of office -- at least some of whom are in the midst of corruption investigations of Bush administration officials and key Republican lawmakers. We also know that they're taking advantage of a handy provision of the USA Patriot Act that allows the White House to replace these fired USAs with appointees who don't need to be approved by the senate.

Given that these new USAs are being plopped into offices currently investigating Republicans and other administration officials and others into states with 2008 presidential candidates, there's certainly ample opportunity for mischief.

David Brin's also picked it up, presumably off Air America.

Here's the problem. We don't have special prosecutors any more, because Congress let the law lapse after Kenneth Starr's investigation. But the U.S. Attorneys report to the executive branch. So we're left with a conundrum: who investigates the executive branch? The courts aren't going to do it. They're really not set up for investigation. So that pretty much leaves Congress. Congress has the power to conduct investigations, generally in the form of hearings, and to subpoena witnesses and documents.

The question then becomes, what would happen if Congress discovered that a high-ranking official was intentionally interfering with investigations to protect him- or herself? At that point, I don't think you could expect a U.S. Attorney to be sufficiently disinterested to be able to prosecute the case in a court of law, and, depending on the official, the court might not even be able to take the case. So Congress might have to resort to an impeachment process.

I don't know enough of the facts to know if there really is a pattern here, though some investigation is probably called for, either by Congress or by an investigative journalist. (Those still exist . . . right?) There sure does seem to be a lot of smoke. I'd just like to know if there's a fire or someone's blowing it.