Once again a summary of why attorney-gate is important from Joshua Micah Marshall. You should read it all, but a key point:
What we seem to see are repeated cases in which US Attorneys were fired for not pursuing bogus prosecutions of persons of the opposite party. Or vice versa. There’s little doubt that that is why McKay and Iglesias were fired and there’s mounting evidence that this was the case in other firings as well. The idea that a senator calls a US Attorney at home just weeks before a federal elections and tries to jawbone him into indicting someone to help a friend get reelected is shocking. Think about it for a second. It’s genuinely shocking. . . .
So what you have here is this basic line being breached. But not only that. What is equally threatening is the systematic nature of the offense. This isn’t one US Attorney out to get Democrats or one rogue senator trying to monkey around with the justice system. The same thing happened in Washington state and New Mexico — with the same sort of complaints being received and acted upon at the White House and the Department of Justice. Indeed, there appears to have been a whole process in place to root out prosecutors who wouldn’t prostitute their offices for partisan goals.