The two protagonists are centre-right president Klaus Iohannis and Liviu Dragnea, head of the Social Democratic PSD party, who is prime minister in all but name.

It was Dragnea's deep-seated ambition to become prime minister after his PSD party won the general election at the end of 2016.

But the 56-year-old was prevented from doing so because of a previous suspended jail sentence for electoral fraud.

But even if he has had to content himself with only being president of the chamber of deputies, it is effectively Dragnea who pulls the strings of power in Romania.

He toppled two prime ministers in just seven months, before nominating Viorica Dancila to the post in January 2017. Her detractors described her as a "perfect puppet".

Over the past two years, the slim, moustachioed leader of the PSD, the successor party to the communists, has courted voters largely in the poor and rural areas of the country with generous political promises.

But he has also focused on relaxing the criminal laws to curtail the activities of country's anti-corruption agency.

His argument is that he wants to "put an end to the abuses suffered by millions of Romanians".

His political rivals suspect this is more about him trying to save his own skin, as he is caught up in two other criminal cases. In one of them, he is already appealing a prison sentence for abuse of power handed down in June.

European officials also accuse him of undermining a much-needed anti-corruption drive in what is considered one of the bloc's most graft-prone states.

Dragnea has repeatedly attacked the EU, which he accuses of "interfering" in Romania's affairs and its sovereignty.

His position echoes similar sentiments from Hungary's nationalist-conservative prime minister Viktor Orban.

Dragnea's increasingly authoritarian style of leadership has also angered critics within his own party.

"Dragnea is no longer the man I knew," said one deputy, Marcel Ciolacu, recently. "He is blinded by power, by pride and by imaginary fears."

In the other corner is Klaus Iohannis, who surprisingly beat off a PSD favourite to be elected president in 2014.

Iohannis has, from the very beginning, been forced to share power with the left, whom he accuses of undermining the rule of law.

Of imposing physical build, the 59-year-old likes to project an image of rigour and seriousness. He has swapped the quiet life of a mayor in the central town of Sibiu for "grand politics".

For some observers, that took him some time to master.

Once considered even by some of his supporters to be too reticent in his resistance to Dragnea's policies, he has since come out of his shell to oppose a range of different government initiatives.

In January 2017, he did not hesitate to join crowds of demonstrators protesting against the ruling PSD party's initial attempts to ease criminal legislation.

Since then, he has been engaged in trench warfare with the PSD, filing lawsuits with the constitutional court and rejecting the government's nominations for ministers and prosecutors.

"I will do everything I can to prevent Romania from taking a step backwards... in terms of the independence of its judiciary," he said earlier this month.

He has also criticised what he says is the government's "lack of preparedness" for its imminent EU presidency.

Even Iohannis' supporters have sometimes complained that he has reacted too slowly or not forcefully enough. This has given the PSD the upper hand in several battles over crucial legislation, they argue.

In contrast, the Social Democrats have complained that he oversteps the mark.

They accuse the president of preventing the government from functioning, of "violating the constitution", and have repeatedly threatened to suspend his powers.

Iohannis has shrugged off such threats.

He argues that such a move would only boost his chances of winning a second term in the next election, due in December 2019 -- where he might face none other than Dragnea.