His leadership collapsed after a string of controversies led to his party losing every seat in his 1987 provincial re-election, leading to his immediate resignation.

[9] On September 9, 1968, a seat was made vacant in Van Horne's home riding of Restigouche following the death of then-Youth Minister Joffre Daigle;[10] nine days later, Robichaud announced a by-election for November 4 to fill the vacancy.

[13] Van Horne ultimately won the by-election on November 4, defeating single opponent and Liberal candidate O. R. M. Brimsacle by 186 votes.

[21] In early April 1969, the Progressive Conservative party called for a leadership convention to be held at Saint John on June 14.

Although it had already been well-established that caucus members preferred Hatfield, it was also clear that this did not indicate his victory, given that this also happened during the last leadership election which Van Horne carried by a three-to-one margin.

[23] Ian R. Ferguson, a 21-year-old University of New Brunswick (UNB) student from Grand Falls who served as the editor-in-chief of UNB's student newspaper The Brunswickan, was the first to declare candidacy for the leadership election on April 15; the reasons he gave for running were because of the "lack in representation of [his] age group in provincial affairs, the lack of government communication with the people of New Brunswick, and specifically because of the sad state of higher education in the province in general".

[27] Additionally, J. Roger Pichette, Alfred Landry, Creaghan and William Cockburn were all speculated by the Montreal Star as being "potential candidates",[28] though they ultimately likely decided against running.

[31] On May 16, Van Horne changed his mind and officially announced his candidacy for leadership, stating that he was urged from all ridings "that [he] should be a candidate for leader".

Ferrabee further wrote that the 1966 delegates had been "persuaded that Van Horne was the only man who could beat Louis Robichaud in an election which they knew then wasn't far off", though Van Horne, on the other hand—being from the northern and majority Francophone part of the province—had the advantage of potentially having the stronger vote from Acadian delegates due to being a much stronger French speaker than the Anglophone-originating Hatfield.

No assets in his name which could've been used to seize and satisfy the debt were able to be found by the sheriff of Restigouche County, who returned the writ marked "nulla bona".

[39] Van Horne was described as being a free spender who substantially indebted the party during his 1967 provincial campaign;[40] the upcoming convention was blacklisted by the American Federation of Musicians from allowing for work to be serviced by its members, as the party hadn't paid a $12,500 bill signed by Van Horne for Don Messer and His Islanders to perform at the time.

[43] That same day, William T. Walker, who had just lost his over decade-long mayoral position in Fredericton earlier that week, declared that he was "definitely in the running", adding that he had "a good chance" of winning in the first ballot.

[48] The day prior, Van Horne attacked Hatfield for "lacking frankness and guts" while also saying that "people resent leadership that is devious and uncourageous".

[42] Hatfield continued to lead the Progressive Conservatives through three victorious re-elections, ultimately having the longest term served by a premier in the province.

[58] The next leadership convention, held in 1989, saw Barbara Baird Filliter emerge as the first woman to become leader of a Conservative party in Canada.