The National Liberal Party (PNL) proposed Ciucă as Minister of Defense of the First Orban Cabinet.[9][8] He was transferred as a reserve on 28 October 2019,[10] being succeeded as Chief of the Romanian General Staff by Daniel Petrescu.[11] He became the Minister of Defense of Romania on 4 November 2019.[12] In October 2020, he joined the National Liberal Party (PNL) to run as a senator for the Senate of Romania in that year's legislative elections[13] and was subsequently elected as well.[14]
On 7 December 2020, following the resignation of Prime Minister Ludovic Orban, he was named acting Prime Minister by Iohannis. He led as caretaker the government until a new coalition government was formed under Florin Cîțu in 23 December as a consequence of the result of the 2020 Romanian legislative election.[15][16]
However, after the Cîțu Cabinet was dissolved through a motion of no confidence on 5 October 2021,[17] Iohannis nominated Ciucă as Prime Minister-designate on 21 October 2021.[18] While the Democratic Alliance of Hungarians in Romania (UDMR/RMDSZ) quickly agreed to renew a minority government with the PNL, the Social Democratic Party (PSD) offered to support him temporarily during the COVID-19 pandemic in exchange for agreeing to 10 measures.[19] He presented his government on 29 October.[20] Having failed to win the support of the PSD or the Save Romania Union (USR), he gave up forming a government on 1 November.[21][22] He was nominated again as Prime Minister-designate on 22 November 2021[23] and was confirmed by the parliament on 25 November after receiving 318 votes in favor.[24] He was sworn in the office hours later.[25]
After Florin Cîțu resigned as president of the National Liberal Party (PNL) on 2 April 2022, followed by a 8-day ad interim leadership of Gheorghe Flutur, Ciucă was elected as the new party leader. He is the third consecutive politician since 2019 to serve as both Prime Minister and president of the PNL at one point, the first two being Orban and Cîțu.[26]
On 26 August 2022, Ciucă signed the first financing contracts of the so-called Anghel Saligny investment program, a foundation whose purpose is to develop settlements for Romanian civilians, formally created as a result of the 2021 Romanian political crisis.[27] Since the investment of the Ciucă-led CNR cabinet, Romania has experienced a shift towards authoritarianism and illiberalism.[28][29][30][31]
In March 2023, Ciucă introduced an artificial intelligence assistant, a "honorary advisor" known as ION, which aims to scan social networks to inform the government of the Romanian people's wishes and opinions.[32] Following the introduction, Nicu Sebe, the coordinator of the research team behind ION, revealed that the event was staged with the AI being unable to generate responses;[33] instead, there was a human operator responsible for selecting pre-prepared responses to anticipated questions.[34] Besides this, it was revealed that out of the 500,000 messages that ION got, only the positive ones were published, with the rest being filtered out.[35]
Nicolae Ciucă has been accused of plagiarizing his PhD thesis by the independent news organization PressOne. Following a year and a half-long investigation, the organization was able to transcribe and digitalize his thesis, "The dimension of the Romanian army's engagement in multinational joint operations", finding that multiple pages of his work were copied, word for word, from other works without the texts correctly attributed to the original authors and lacking the requisite quotation marks, as required by academic norms.[45][46][47] During the investigation, journalist Emilia Șercan discovered that at least 42 out of the 138 pages in the doctorate thesis were plagiarized and that 94.2% of the plagiarized content in Prime Minister Nicolae Ciucă's thesis originates from non-digitized works, which could not be detected using anti-plagirizing software. Nicolae Ciucă denied the accusations, stating they "cannot be scientifically proven."[48]