It seems to make an assertion that I often find elsewhere; essentially, that participation by Iraqis in an election automatically means that they see elections as legitimate and see the governemnt as legitimate; thus, a high turnout is a repudiation of the insurgency.
What is rarely considered is that a love of democracy isn't a requirement for participating in an election. Nor for that matter does everyone participating in an election have to view it as legitimate; they may just look at the fact of the election and decide that it is in their interest to participate.
Put another way, it is totally possible for a person to vote in the election and yet still view the resulting government as illegitimate (or as opposed to his interests; self-interest or interest of one's group is often the motivation rather than an actual moral principle). It is also possible to vote in the election as one way of trying to get power while simultaneously supporting the insurgency (and viewing foreign fighters from terrorist groups as allies of convenience in the current campaign) as another way.
So even a high turnout in Iraqi elections by Sunni Arabs doesn't necessarily mean a loss of support for the insurgency in the Sunni Arab population; it just means that the Sunni Arabs are seeking power through more than one route.
And on a related note, high Shiite Arab participation in the election may not necessarily mean heavy Shiite Arab support for democracy in principle; rather, it could just indicate a desire to take advantage of their greater numbers (relative to the Sunni Arabs) in order that the Shiites escape from under the Sunnis' thumbs. Perhaps a Shiite-Arab led Iraq is more democratic, in the sense that the majority ethnic group is ruling, but it does not necessarily mean that the Shiites view democracy per se as a viable way to solve political questions.
Granted, high voter turnout is a good thing. But we have been told since 2003 that the insurgency was losing steam because it was losing support amongst Iraqis, so color me skeptical of any claims that "Now that we have 'X' (e.g., elections, a governemnt, a constitution, high voter turnout) the insurgents no longer have any reason to continue the insurgency, so it will die down."
Of course, there is also the dynamic between the foreign fighters and between the homegrown insurgents. If there is a rift there, as Omar suggests in the post linked to above, that could be helpful, at least in reducing coordination and hopefully reducing the number of terrorist suicide bombings (as foreigners seem disproportionately represented in this type fo attack). On the other hand, as the Iraqi Sunni Arabs are in direct competition with the Shiite Arabs, and as there is little love between them, I am not so certain that the insurgency doesn't welcome any terrorist attacks by foreign fighters that kill the rival Shiites.
That is all.