First of all, it is difficult to objectively look at the likely 2012 presidential primary calendar and make the argument that it is compressed. That is even more true when the evolution of the calendar is considered. Recall that the plan was for Iowa, New Hampshire, Nevada and South Carolina to hold February contests while the remaining states could choose dates on or after the first Tuesday in March (through the second Tuesday in June). If Florida, as was talked about early on, had carved out a spot between South Carolina and Super Tuesday, then perhaps we could talk about a compressed calendar. But even then, that description is a stretch. That is an even tougher sell when you consider that the same basic alignment and spacing is being preserved among the first four states and Florida; they are just a month earlier now. Couple that with the fact that most of the states scheduled to hold February contests entering 2011 opted to move back and move back to dates other than the earliest date allowed by the two national parties -- the first Tuesday in March.
How can the calendar be compressed if there is no noticeable clustering among the early contests? Now, if Iowa and New Hampshire end up going within days of each other then perhaps those two contests could be described as compressed. The overall calendar, however, is not.
There are two items that are being talked about simultaneously and both need to be extricated from each other to some extent. There is invisible primary campaigning and there is the calendar. The calendar is as extended as it has ever been, and with contests even more evenly dispersed through March, April, May and June, it is the least compressed it has been since the early 1980s. There is no compression to the calendar.
Where there is compression -- and it is due to the elongation of the calendar -- is in the amount of time between now and the first contest. That is the end of the invisible primary; as it fades and yields to actual voting. The time the candidates have to campaign, raise money, garner endorsements and organize prior to Iowa and/or New Hampshire has been compressed greatly because of the decision in Florida and the subsequent jockeying among the first four states. And no, it should not come as any surprise that that time crunch more negatively affects the candidates whom either haven't done this before and/or who are not the current frontrunner for the Republican nomination. Any time taken away from candidates attempting to get to the same level as Mitt Romney gives the former Massachusetts governor an increased advantage. Mayer and Busch (2004) have shown that.
To his credit, Altman does get around to the notion of an accelerated schedule, but not before having seemingly lumped the overall primary calendar into the equation first. There is a distinction to be made between the invisible primary and the primary calendar itself, semantics-based though it may be, but FHQ will not be so naive as to suggest that the two are completely separate. The compression of the close of the invisible primary makes it harder for non-frontrunners to make the case in the early states which affects the results there which has an effect on later states, etc. [And that chain reaction begets the "Romney is inevitable" meme that folks are starting to prematurely make.]
There is an overall sequence to this that includes the presidential primary calendar and that overall sequence has been compressed as those contests loom. But the presidential primary calendar itself is not compressed. The primary calendar portion of that overall sequence is anything but.