The 2004 PR Elections, where after Sila María Calderón forewent a second term, incumbent Resident Commissioner Aníbal Acevedo Vila went for the governorship and defeated former Governor Pedro Rosselló in his comeback bid for the Governorship.
Gov. Calderón didn't run for reelection likely due to a personal "scandal" that engulfed her early in her administration, where she divorsed her husband of 23 years for a member of her staff whom she dated and maried in 2003.
Further, this term resulted in a large ammount of politicians and other public servants from both the PPD & PNP being tried and convicted/aquitted of corruption, with Former Gov. Pedro Rosselló asking for pardons from members of his cabinet - But notably, not himself.
In any case, due to moving to Virginia in 2001 when his term expired, Rosselló had to contend with charges of carpetbagging - only moving to run for Gov - in addition to unverified allegations that he knew about the corruption going on in his cabinet but did not do anything about it.
As such, despite his personal popularity, these allegations, and Aníbal's campaign to specifically target and gain votes from the PIP, increasing the amount of Melonismo(PIPs who vote PPD) on the island to stop statehood, led to Rosselló losing by a 0.18% Margin, and less than 3,000 votes.
Aníbal's Margin of victory in fact was smaller than an unspecified - yet not unprecedented - legal electoral quirk due to PR's Ballot design, Statewide ballots with 3Xs (See bellow) with a person voting for one party's insignia, and then another party's gov and resident commissioner candidates.
These "Pivasos" (Known as such since they were predominantly from the PIP), were contested by Rosselló as spoilt Ballots, as Mixed votes normally only have two Xs - whereas Aníbal and the PPD successfully argued that they had been counted as though they were candidate votes with an insignia in the past.
This was decided in the Supreme court of Puerto Rico, which ruled in a split 4-3 decition in favor counting the Pivasos as votes for Aníbal acevedo Vila, leading to his ultimate victory over Pedro Rosselló.
In the 2004 Resident commissioner's election, Former Secretary of Economic Development Luis Fortuño (R-PNP) triumfed over Senator Roberto Prats. (D-PPD)
Fortuño's victory was mainly due to a mixture of him being less tied to the scandals of the Rosselló adnimistration, and Prats benefitting less than Aníbal from the Campaign to gain PIP votes due to Aníbal being more of a Soberanista, and going more agressively after PIP Votes than Prats.
In terms of Mayoralties the PNP received a large victory, mainly due to recovering ground lost in 2004, regaining burgeoning Strongholds like Gurabo and Santa isabel, old strongholds like Adjontas and Toa Baja, and swing Municipios like Morovis, while holding San Juan.
However, the PPD did have some victories in this Arena, gaining the swing municipio of Quebradillas, while winning the PNP municipios of Aguas Buenas and Naguabo.
In the Senate the PPD faced one of their worst defeats, with the PNP gaining 10 seats over the PPD for an 8 seat majority (17 PNP-9 PPD). Mainly due to their rebound in the North Coast and northeast tip - whilst the PPD underperformed in Cabo Rojo and San German.
Note: the gains are from the election of 2004, as Senator Sergio Peña Closs(PNP-At Large) switched an independent from PNP and later returned to the PPD(after leacing it in 1996) in 2002. (The PNP was awarded another Seat in 2002 under the minorities law when Sen. Sergio Peña went to the PPD.
in the House elections a similar thing happened, with the rebound of the PNP from their 2000 defeat in Al Cordillero Central, north Coast Northeast Tip and the San Juan Metro, alongside the PPD's underperformance in Cabo Rojo & San German allowed the PNP to gain a sizable 12 seat (31 PNP-19 PPD) Majority.
Note: the gains are from the election of 2004, as Representative Jorge de Castro Font(PPD-At Large) switched to an independent from PPD and later switched to the PNP in 2002