The 1970s ushered in a new era in Guam politics.
Prior to the 1970s, Guam, more or less, was a one-party island : the Democratic Party. The Democrats controlled Guam elections since 1960, and, prior to 1960, its predecessor, the Popular Party, also ruled in Guam politics. Only in 1954 did the Popular Party lose control of the Guam Legislature when enough members broke away to elect a new Speaker and form a new party, and only in 1964 did the Democratic Party actually lose a legislative majority due to a general election.
But by the 1970s, Guam had an elected, Republican Governor. By the 1970s, a small number of Republicans were elected to the Guam Legislature, which had been, election after election, in the 1960s, completely in the hands of the Democrats, winning all 21 seats. In 1974, the Republicans captured the majority in the Legislature. By the 1970s, Guam was truly a two-party island.
Part of the reason for this was the expansion of the Government of Guam in the 1960s which continued under Republican Governor Carlos Camacho's term in the early 70s. Camacho appointed many young college graduates returning to Guam to government positions. Many of these young civil servants, and their families, became Republican supporters.
Another reason for the growth of the Republican Party was the arrival of many Filipino immigrants in the 60s and 70s. When they obtained US citizenship in time, and thus could vote in Guam elections, many of them voted Republican.
How was this new partisan scenario spread out across the island? Were all villages bipartisan now? Or did some villages lean more towards one party over the other?
Based on each village's general voting pattern in legislative and gubernatorial elections in the 1970s, as well as looking at each village's trend in voting for its Commissioner, what we now call the Mayor, we can form a general idea in answer to these questions.
Tamuning. This was historically the Republican bastion on Guam. From the 1970s on, Tamuning has always elected a Republican Commissioner or Mayor. There are some election years where there isn't even a Democratic candidate for those positions. In 1978, Tamuning was the lead village of election District Two, which had seven seats in the Legislature. All seven seats in District Two were won by Republicans.
Agaña. The capital city always elects, election after election, since the 1970s, a Republican mayor and Republican candidates for Governor and the Legislature get high votes in Agaña.
Sinajaña. This village is so Democrat, it has never elected a Republican Commissioner or Mayor, and many times the Republicans don't even bother presenting a candidate. In legislative and gubernatorial elections, Sinajaña can usually be counted as a safe Democrat village.
Inarajan. In the 1970s, Democratic candidates for Governor or Senator could count on a lot of votes in this village.
Merizo. Also considered a very safe Democratic stronghold in the 1970s.
Umatac. Talofofo. Chalan Pago-Ordot. Piti. Yoña. Mangilao. Barrigada. These villages, in the 1970s, were still considered Democratic territory, but things were beginning to change. Some of these villages had Republican Commissioners (e.g. Bernardo in Yoña for many terms). Chalan Pago was considered more Democrat while Ordot had significant Republican support. Umatac started to see more Republican votes in the latter 1970s. When Barrigada Heights was opened, Barrigada saw more Republican votes.
Mongmong-Toto-Maite. Agaña Heights. Agat. Santa Rita. Asan-Maina. Again, in some of these villages, there were significant Democratic voters. Asan was considered, in the 70s, more Republican while Maina was more Democrat. Mongmong more Republican and Toto more Democrat (Maite was considered a Republican area). Agat had a visible Filipino minority which boosted Republican support. Santa Rita had Republican mayors (Pete Roberto and Juan Perez, better-known-as Ducket). Agaña Heights leaned more towards the GOP, but for many years, its Commissioner (Frank Portusach) was Democrat.
Dededo. Yigo. These northernmost villages, at times, could be counted on to lean slightly toward the Republican side in the 1970s, but the Democratic support there was also strong. This can be seen in the 1978 senatorial race, which was done by districting. Dededo and Yigo formed District One, with five seats. In the 1978 election, 3 of those seats went to Republicans (Espaldon, Lamorena, Kasperbauer) and 2 seats went to Democrats (Dick Taitano and Joe T. San Agustin). But, two years later, in 1980, the last time senators were elected by districts, 3 seats in District One went to Democrats, and two went to Republicans.