He experimented with creating a third party, negotiated common platforms for the various opposition forces, including the Conservatives and the Junimea society, during contiguous National Liberal administrations.

Fleva was notoriously involved in the major scandals of the 1880s, when his ridicule of National Liberal power generated street battles and sparked two separate shooting incidents.

At the time, "Flevist" groups were seen as the leading voice of middle class discontent, and formed one of several currents pushing for the adoption of universal male suffrage.

[6] Upon his return to Romania, Fleva spent a period tending to his lands in Putna County, pursuing interests in agriculture and horse breeding: he judged in ploughing contests at local fairs, and received a silver medal for his mare Diditia.

[15] The period saw him joining a defense team for soldiers and civilians prosecuted for their roles in the "Republic of Ploiești" conspiracy—all of them, including liberal leaders Ion Brătianu, C. A. Rosetti, Eugeniu Carada and Anton I. Arion, were acquitted.

[9][16][17] Fleva, who rested his defense tactic on contending that Epureanu's men had incited and misled Romanian republicans,[16] publicized his speeches in court as the 1871 booklet Procesul lui 8 august.

His hold of the seat was contested by a rival politician, Potoceanu: in early 1875, just before the scheduled election the Assembly plenum ruled to remove Fleva from his position of deputy.

[18] Subsequently, Fleva played a part in the effort to unite a single liberal opposition against the conservatism of Prime Minister Lascăr Catargiu and other political leaders closest to Carol.

It was soon joined by the main anti-Catargiu factions: a moderate current spearheaded by Ion Ghica and Mihail Kogălniceanu; Nicolae Ionescu and his "Fractionists" from the eastern Romanian province of Moldavia; and a group of former conservatives such as Epureanu.

Fleva was part of the Editorial Committee, which included almost all of the liberal leadership (excluding C. A. Rosetti), and employed the young satirical journalist Ion Luca Caragiale as copy editor.

[24] At this point in time, the liberal factions found support from Stephen "Mazar Pașa" Lakeman, who, as a loyal subject of the British Kingdom, may have intended to steer Romania away from its Austrian commitments.

[40] Fleva may even have been partly responsible for sacking Eminescu from the office of librarian, back when the National Liberals first began evaluating the loyalties of public servants.

His speech was reviewed in 2012 by academic Codrin Liviu Cuțitaru as a classic misinterpretation of that principle, since it validated a permanent "state of revolt" among those who felt disenfranchised.

[54] As Mayor, Nicolae Fleva was noted for setting up Sfântul Anton Market (near Manuc's Inn) and Eforiei Bathhouse (by Cișmigiu Gardens),[11][47] and, in following with his passion for horses, for donating the Băneasa grounds which became Bucharest's Racecourse.

[11][47] Some have nevertheless described these as unimportant achievements; literary historian Ioana Pârvulescu summarizes his term with the words "he did nothing",[61] while, according to Apostol, Fleva "left no trace on how Bucharest developed".

Under their supervision, the crowd trying to occupy the building and make it an anti-government fief found its access blocked by pro-government men (soldiers, mounted Gendarmes, police or simply National Liberal militants).

[11][56][69][73][74] Fleva stood accused of inciting the riots, and even suspected of the murder: police alleged that a gun had been found on his person,[11] but other reports state that none of the deputies was armed.

"[56] The pro-Conservative daily România Liberă, whose editor Duiliu Zamfirescu was a passionate critic of Fleva,[46] suggested that there was an unbridgeable gap, in both doctrine and interests, between the former two sides of United Opposition: "On one hand the Junimists with the Liberal-Conservatives and the Young Conservatives, supporting the government and holding the door open for all men of decency who, through similarity in ideas, may wish to work for the actual consolidation of the state and a true betterment of Romanian society; on the other the defeated collectivists, who will put out for any liberal who will fight the government, be they Fleva, Panu, Grădișteanu and Dim[itrie] Brătianu.

A number of local guilds, including the cooperative movement of Dimitrie C. Butculescu, supported him in this effort, but he only finished in a distant third; the Conservative Pache Protopopescu won the day.

[85] During that time, Fleva was especially interested in the fate of Romanians living in Transylvania or in other parts of Austria-Hungary, many of whom were complaining about government abuse and Magyarization policies (Transylvanian Memorandum).

[14] This interval also made Fleva a prime target of celebrated Romanian satirist Ion Luca Caragiale, once an Alegătorul Liber colleague, who had by then moved closer to Junimist politics.

[94] The Prime Minister, notorious for his lack of authority,[95] and his Internal Affairs subordinate despised each other, particularly since Fleva realized that Sturdza would never apply the "Program of Iași".

[97] Sturdza interpreted this work as a sign of disloyalty, and the National Liberal paper Voința Națională made a show of Fleva, publishing allegations about his conduct in both public and private.

[92] He is believed to have coined the term Oculta ("The Occult [Faction]"), which was subsequently used to designate the secretive triumvirate of National Liberal figures, allegedly Sturdza's puppet-masters: Carada, Pache Protopopescu, Gogu Cantacuzino.

[104] Subsequently, the parliamentary Flevists (described by one Transylvanian observer as "Mr. Fleva and seven of his comrades") reluctantly voted in favor of some National Liberal laws, but aimed most of its activities against Sturdza's cabinet.

[106] In tandem, a second dissident faction, formed around Petre S. Aurelian and Drapelul newspaper, and likewise attached to electoral reform projects, took still more voters away from the National Liberal Party.

In a letter of June 1898, he made special note of these developments: "All the Liberals, the Drapelul men and of course the Flevists too, are utterly ignorant (except for Sturdza and Beldiman [...]) and enrich themselves through politics.

[111] On April 11 of that year, Premier Gheorghe Grigore Cantacuzino came to power after the fall of another Sturdza cabinet and four months of government crisis,[111] placing Fleva in charge of the Ministry of Agriculture and Royal Domains.

[112] However, the election itself dampened his ministerial ambitions: in Slatina, the peasant voters were allegedly instigated to rebel by the political boss Alexandru Bogdan-Pitești, leading to a massacre.

He quit the party, which had by then allied itself to the National Liberals, noting that Ionescu no longer stood for the initial goals: updating the 1866 Constitution and promoting land reform.