Much of the debate about the Gonzales Eight Massacre has been muddied, sometimes through deliberate obfuscation, because the word "political" has several different meanings. When we say that U.S. Attorneys are "political" appointees, we mean that they get their jobs through political connections and that once in office they can be required, even by threat of firing if necessary, to adopt the policy priorities of the administration in Washington. A U.S. Attorney who resisted the White House decision to seek the death penalty with greater (or lesser) frequency, or to devote prosecutorial resources to drug cases rather than insider trading cases, could be legitimately sacked for reasons of politics in the sense of policy. A U.S. Attorney cannot legitimately be fired for failure to prioritize corruption cases of Democrats over Republicans (or vice-versa). The distinctions can blur where a seemingly legitimate policy objective is used as a pretext for partisan aims. Democrats tend to be the target of voter fraud prosecutions (because of the assumed preference for Democrats of the new voters likely to register en masse, i.e., immigrants, the poor, and minorities), while Republicans tend to be the target of bribery and extortion prosecutions because supporters of Republicans tend to have more money than supporters of Democrats. These are broad generalizations which may not even be true, but to the extent that they are, a policy of targeting a particular kind of corruption case could be pretextual and would, if so, be highly problematic.
The underlying distinction between politics as policy preference and partisanship is broadly familiar from the controversy over Bush v. Gore. Some hard-core legal realists (I have in mind Jack Balkin and Mark Tushnet but there were others) took the case as simply confirming what they had always thought: that judges make political decisions. But most critics of the decision did not endorse this sweeping critique. They thought that there is a difference between a judge deciding a case involvingthe constitutionality of abortion restrictions or affirmative action in a way that lines up with her policy views on these issues, and a judge deciding a case based on which political party would benefit in the particular case---as many of the academic critics and even more of the general public thought the Supreme Court did in Bush v. Gore.
It's possible that I'm over-reading the reaction to Bush v. Gore. Perhaps the public generally hold a highly formalist view of the law but don't pay much attention to Supreme Court decisions. Then, they tune in and observe partisan politics and are horrified, but had they tuned in sufficiently for other cases they would have been almost equally horrified by the ordinary politics of judging. That's possible but I actually give the public more credit. The periodic references to the judicial appointment power in Presidential campaigns suggest that at least a substantial portion of the public are at least aware of the difference that individual values make to judging. Yet (rightly or wrongly) they sensed that something different was happening in Bush v. Gore. If that's right, then the public can be made to understand the difference between politics as policy choice and politics as partisanship. But to make it work in the current context, Democrats and other critics of the Gonzales Eight Massacre need to stop calling the firings "political" --- a word that invites double-talk from the likes of Tony Snow, FoxNews et al --- and start referring to the firings as "partisan."