I just read Dr. McNinch's column "Third Party Solution" (Marianas Variety, 10-23-2012).
In it, he puts forth a basic theory that "when democrats run the executive branch, the republicans get exiled to the legislature" and that "When republicans take over the executive branch, legislative power is affected by rank recruitment into director positions."
He says that "Few Republicans would want to risk a stable director position for the unstable legislative branch." I believe he does not mean to imply that democrats and republicans are driven by different impulses, but is trying to offer a political "supply side" explanation for imbalances in the legislature. Apparently, the reason why the Republicans have held the majority only about 1 1/2 terms (the 28th and the 29th Legislatures) is that a there was an adverse supply shock which caused Republicans to join the Republican Camacho-Moylan/Camacho-Cruz and Calvo-Tenorio administrations and, therefore, abandon the Guam Legislature.
I have a simple supply-side explanation which I think can rival Dr. McNinch's. Most of the legislatures since the 26th have been within one or two seats of switching the majority. In 2002, four Republican incumbent senators and one Democratic incumbent senator dropped out to participate in the gubernatorial election.
Democratic senators went from 7 to 9, and Republican senators went from 8 to 6. Two of those prominent Republican former senators came back to the Legislature in the 28th. Democratic senators went from 9 to 6 and Republicans went from 6 to 9, but most of that is accounted for by the return of just those former senators.
In the 2006 election, two Democratic senators dropped out to contest the gubernatorial election and another pair of incumbents (1 Dem, 1 Rep) left. Even so, the Democratic Party went from 6 to 7 and the Republicans went from 9 to 8 in the election. The midterm returned Senator B.J. Cruz to the legislature. In 2008, without any major changes, the Democrats gained two more seats (to 10) and the Republicans dropped to 5, although the lead was narrowed with the midterm election of Senator Tony Ada. The most recent general election saw one Democrat and three Republicans drop out to contest the gubernatorial race, but the Democratic lead remained at 9-6.
I would add that despite the explanation which Dr. McNinch offers, few incumbents were lured away by the administration. He might be somewhat right as one thinks about first-time entrants, although that would be very anecdotal (not that there is anything wrong with including such evidence). Obviously I am missing a lot of details even on the "supply side" of potential legislators, but I do not think there is sufficient evidence to support the connection between the party of the administration and the lack of a majority from the same party. As Gunnar Myrdal, my favorite economist, wrote in Beyond the Welfare State, "Correlations are not explanations and besides, they can be as spurious as the high correlation in Finland between foxes killed and divorces." (By the way, for those who are interested, you can find very cheap copies of this book on Amazon or other online booksellers.) Equally important, even where there is a historical pattern, it can end abruptly, as the famous phrase says: "The trend is your friend until the end."
The most important fact is that demand is another major factor. Politicians do not just step forward, then get inaugurated: they must convince a sizable bloc of voters to vote for them. The people of Guam still have to decide who to support. It seems to me that there is still much to be investigated both in Guam's politics and how elections really end up selecting politicians to serve the public.
I did not quite understand how Dr. McNinch came to the conclusion that the existence of a third "non-aligned" party would change the dynamics in a positive way. I am supportive of the idea of a third party, although I do not think it likely that one will emerge and thrive (it's probably more likely that one of the existing parties could be reformed by the concerted effort of a Guam-scale mass movement). I have further doubts that a third party would really be "non-aligned". If a third-party is formed with the intent of influencing politics, it will probably tend to be more closely related to one party over the other. In any case, the idea of a successful up-and-coming third party strikes me as a bit utopian, but I could be wrong.