Deep into the Period of PPD Dominance that lasted between 1944-1968, the 1960 Election was the first true challenge to Muñoz Marín's and the PPD's Power, and resulted in the largest Margin of Victory in all of the Four elections that Muñoz Ran in, even as he fell under 60%
To this effect, this election is also characterized by the rise of the Short-lived Partido Acción Cristiana, A party that rose out of the Catholic Church's resentment toward Muñoz-Marín's and the PPD's Natility policies.
With those policies being a general laissez-faire attitude towards sterilization (Which the church was opposed to) and being major proponents of birth control on the island.
That, in addition to a controversy that arose when an At-Large PIP Rep proposed a bill that would provide for religious teachings in PR's Public Schools, said bill was panned by the PPD - & even recieved personal criticism from Muñoz - led to conflict between the PPD & the church
The conflict between Muñoz and the Church was so grave, that they had in fact publicly fought with the Arch-Bishop of San Juan, and the Bishop of Ponce, to the point where preceding the 1960 election, the Bishops declared it a Sin to vote for the PPD on the mainly Catholic Island.
To this effect, Muñoz gave the order to all PPD Candidates to not discuss the feud under any circumstances, for how delicate it was, choosing to tackle it himself.
Furthermore, Muñoz found a legal loophole in the Church's declaration: Instead of voting íntegro for the PPD, Muñoz instructed his supporters to vote for the PPD's candidates individually, sidestepping the matter of Sin as people weren't voting for the PPD, but for its candidates
This occurred in addition to Muñoz-Marín highlighting the importance in the seperation of Church and State, declaring - in an afront to the Church's traditional political powers that (translated) "I don't tell everyone how to pray, and the Bishops can't Tell you how to vote"
The resulting Landslide, a 26.16% margin, and Muñoz reaching over 58% of the vote with a minimal hit to the Voto íntegro, ended up being a vindication for Muñoz and a testament to his absolute popularity in this period.
This election was also a major repudiation of the Catholic Church, as they had gone all in on the Partido Acción Cristiana, which received only 6.62% of the vote. Forcing them to patch up relations with the PPD, but the damage was done, & this election affirmed secularism in PR, for the most part.
The Concurent Resident Commissioner's election was also significant as it was the first time that the PPD's pull with the congress had been weakened to the point that they Couldn't pass changes to the Estado Libre Asosiado
This became apparent due to the failure of the Fernós-Murray Bill, which would have given Puerto Rico More autonomy, and a deeper tie with the Union including the Presidential vote.
Unsurprisingly, this was Panned by the committee, and the PPD swore off any changes to the Estado Libre Asosiado, beyond seeking to define it's existing relationship whithin Federal Jurisprudence, through the compact theory*
This election also saw the PPD sweep all the Mayoralties on the island, except San Lorenzo. (Which was the last Municipio to come under the PPD Banner)
In addition, due to a splinter in the PIP vote, with some leaving to the PPD & others to the PAC, this was the first election since before 1952 that they fell out of the legislature entirely, loosing all their seats to the Pro-Statehood Partido Estadista Republicano, & the Conservative PAC.