[1] In 2015, an allegation of plagiarism was lodged against Oprea with regard to his thesis; he responded that the source of the complaint was an individual he had fired and who was pursuing a vendetta.

[3] A 2023 ruling by the High Court of Cassation and Justice annulled the order withdrawing his title of PhD, prompting Oprea to claim he had been cleared of plagiarism.

[1] In 2003, Oprea joined the PSD, and aside from serving in the Năstase government, he became president of the party's Ilfov County branch in 2004 and of its defence policy department in 2006.

At the 2004 election, he won a seat in the Chamber, where he served on the joint parliamentary committee providing oversight to the activities of Serviciul Român de Informaţii (SRI) and worked mainly on legislation affecting that agency.

[9] Oprea announced his priorities as minister to be security for citizens, in particular the maintenance of order in large cities; decentralisation combined with a strengthening of local institutions; and for Romania to join the Schengen Area by 2011.

[11] The affair caused some tension in the coalition government as well: Prime Minister Emil Boc of the PD-L signed Oprea's appointments also without consulting Geoană.

[12] Following several days of scandal and with no sign of support from President Traian Băsescu,[13] Oprea resigned his post after three weeks on the job, claiming he had acted "properly and legally" but that the appointments had "disturbed certain people" and he was unwilling to be a "puppet minister".

[21] At that point, incoming prime minister Victor Ponta, despite having criticized UNPR members as "traitors" and "undercover officers", reached an agreement with Oprea, who provided parliamentary support to the new government.

[20][23] In January 2014, following the resignation of Radu Stroe, Oprea returned as Interior Minister on an interim basis, and on a permanent one after Ponta formed a new government in March.

[30] In March 2016, the National Anticorruption Directorate (DNA) opened two cases of abuse of office against Oprea: one for illegally using a motorcade, and one for purchasing a limousine using government funds.

[33] This move sparked a protest before the Senate building that drew some 3000 individuals, prompting Oprea to announce his resignation and remove any shield of parliamentary immunity.