In one of 2020's Many Electoral suprises, The PR Arecibo District flip was one of the ones that I found to be very unexpected. With three term incumbent Ángel Martínez, and two term incumbent José Pérez Rosa both ultimately falling to their PPD Challengers; Elizabeth Rosa Vélez & Rubén Soto Rivera
In retrospect, the overall result can be explained by the overall anti-incumbent sentiment felt in the 2020 Puerto Rican elections.
But nonetheless, this was a supprising result observers, as other than Bayamón the Arecibo District has been the District most securely in PNP hands since 1992 (despite a close call in 2012 where the PNP nearly lost one seat) with them only loosing it once before(2000).
The PNP's Ultimate downfall in this nail-biter of an election came in their Close margin in the Municipio of Arecibo itself, despite winning the Municipio, the fact that their combined margin was only 2.1% (down from 10.3% from 2012) cost the PNP these seats.
In any case, If Arecibo returns to being a Strong PNP Municipio, the Days of the PPD holding both of the Arecibo Senate district's seats are numbered.
Lastly, an interesting fact with regards to this district, in Febuary 2005 after the Resignation of one of this districts Senators the PNP chose former Governor Pedro Rosselló(D-PNP) to hold this seat.
Rosselló then engaged in a power struggle where he tried but failed to take the Senate presidency from Kenneth McClintock(D-PNP).
A little Addendum I'd like to add is that looking at the results by state house district tells us a similar story as too the Precinto Results:
By Percent obtained
By Margin obtained
Namely that the underperformance in Arecibo 27 (district 14) is what destroyed the PNP here as if it were higher it would have given them the votes needed to overtake the PPD from their Vote margins in Distritos 11 & 12).
Note* despite the margin being so small I am focussing on Arecibo as it is the most stark underperformance, and it being that bad a performcance I am focusing on it.
Note** The PNP Senators also underperformed the Distrito 14 Candidate by ~11% Thereby helping to shocase how this was the underperformance that cost them their seats.