The opposition was completely restructured, with left-wing Union of the Forces of Progress, centre-left Rally of Democratic Forces and Haratine minority interests People's Progressive Alliance losing all of their seats in the National Assembly, with left-leaning Hope Mauritania replacing them as the hegemonic left-wing opposition.

Ould Abdel Aziz was subsequently charged with "corruption, money laundering, illicit enrichment and abuse of influence" by the Public Prosecutor in March 2021 and referred to court in June 2022.

On 18 October 2018, a month after the previous parliamentary elections, the Unionist Party for the Construction of Mauritania (PUCM) voted to merge into the UPR.

[28] Political analyst Abdellahi Ould Mohamed Lemine told Maghreb Voices that he believes that adopting this option in voting will cancel the current method of election, which relies on ability of voters in choosing different parties per ballot (national lists and constituency), and that such reform would benefit the largest parties, especially El Insaf, which is capable of fielding candidates in all constituencies.

The party's spokesperson, Salek Ould Sidi Mahmoud, affirmed that he considers the issue as "an indication that does not encourage confidence in the government's commitment to the [election reform] agreement" and said that "the proposal to unify the card was put forward under the pretext of reducing the void cards, but it is a fact that greatly limits the voter's freedom of choice".

[38] On 22 December 2022, Hope Mauritania was presented as a left-leaning opposition alliance which was joined by several major politicians, including ex-MP Kadiata Malick Diallo (ex-UFP) and MPs Mohamed Lemine Ould Sidi Maouloud (ex-Choura) and Elid Ould Mohameden (RFD).

[53] Tewassoul asked for voting to be stopped in four polling stations in a village of Boutilimit and the dismissal of the head of the National Independent Election Commission (CENI) in the department of Boutlimit.

[56] CENI announced during the scrutiny of votes that it detected the manipulation of the results of the El Mina department of Nouakchott where some votes were transferred from the null and neutral cards to a particular candidate, confirming that the matter had been corrected, and judicial procedures had taken its course after a candidate complained about the results and an inner investigation was launched.

[64][65] The opposition also announced their intention to form a committee to jointly file appeals on the election results and warned that the "current electoral crisis", if not dealt with wisely and quickly in a consultative framework, would turn into a political one.

[67] Leader of the Democratic Alternation Coalition and re-elected deputy for Sawab+ Biram Dah Abeid was arrested on 24 May[68] after he declared that if the results of the elections are accepted, then "the free Mauritanians will carry weapons against the current regime" during a political rally the day before.

He also said in his speech that he was "committed to peace" but that he "wouldn't lie to the Mauritanian people" and that "election fraud was the reason the army couped former president Maaouya Ould Sid'Ahmed Taya".

[73] A protest was held in front of the Security Department by members and supporters of the Initiative for the Resurgence of the Abolitionist Movement, which Dah Abeid heads.

[78] Biram Dah Abeid was released after two days of arrest on 26 May, with him returning to his house in Riyadh, Nouakchott.

He declared after his release that he expected to be detained until after the 2024 presidential election as part of an operation to "prevent a peaceful transfer of power" and that his arrest was done to thwart or disrupt the opposition rally held on 25 May.

[80] Five political parties were legally deregistered on 19 October 2023 after failing to obtain 1% in two consecutive local elections.