I completely endorse the distinction that Ed Kilgore makes but appears to feel isn't really necessary between "clear the field" and "dominant opening position" when talking about Hillary Clinton and the 2016 Democratic presidential nomination.
I think, that is, that the distinction is necessary. To me, "clear the field" means something pretty specific: that no other plausible nominee would run. So I wouldn't say that Al Gore in 2000 cleared the field; he solidly beat Bill Bradley, and it was probably over before the Iowa caucuses, but Gore had to run a real primary campaign against a candidate who certainly could have been nominated.
I mean, around the margins, I can imagine arguments...did George H.W. Bush clear the field in 1992 when Pat Buchanan ran? Did Richard Nixon in 1972, when two members of the House ran? But Gore clearly didn't. And my guess is that Clinton won't.
It seems to me this is quite a meaningful distinction, too. For one thing, it could affect whether she chooses to run or not. If she really could have the nomination without having to run through the primaries and caucuses...well, that's a lot easier decision than one that would involve defeating one or two or three candidates, no matter how heavily she would be favored.
I'm also not quite ready to conclude exactly how dominant she would be if she ran. Clearly, she's would be a heavyweight, top-tier, contender. But there's a long time to go, and it's not clear yet how Democratic party actors will think about this when they really have to commit. Basically, the reasons why she's an overwhelming apparent favorite right now -- she's well-known, well-liked, clearly qualified, clearly can raise money, and to some extent there may be a feeling that she's earned it -- may not turn out to be the things that actually yield her the overwhelming support of party actors in 2014 and 2015. I'm not saying that she wouldn't win, or even that she isn't an overwhelming favorite...I'm just saying I'm not sure yet. All we can say for sure is that she would be a heavyweight/top tier type candidate. Which is a lot, but not everything.