ROME - Five years ago, Matteo Salvini confirmed his status as a rising star of European far-right politics when his League party swept a third of the vote in Italian EU parliamentary elections.

His fortunes have since waned even as Italians have ushered in their most right-wing government since World War Two, his popularity eclipsed by the ascent to power of his ally Giorgia Meloni and her nationalist Brothers of Italy party.

Salvini's League, a junior partner in the rightist coalition, is polling below 9% ahead of new European parliament elections in June, while Meloni's party hovers close to the 30% mark, cementing its position as the largest force in Italy.

In an effort to rekindle support, Salvini has driven even further to the right on issues such as crime and relations with Brussels, but the shift has not yet moved the polls his way.

One of the League's European lawmakers, Gianantonio Da Re, told Reuters that Salvini would face internal pressure to step down as leader unless he stopped the rot in the June election.

"We got 34% five years ago. If we get 8% this time, someone will have to answer for it," he said.

League Senator Gian Marco Centinaio - a senior Salvini ally - ruled out the prospect of a looming leadership showdown, or the likelihood of the party performing badly in the EU election: "This possibility doesn't exist," he said.

But the pressure is building.

Salvini's rightward lurch has caused discontent within his own party ranks and poses a problem for Meloni as she seeks to present her government as a reliable partner in Europe and beyond, according to some politicians, pollsters and academics.

The future of right-wing politics across Europe is also in focus, the experts said, with Salvini the flagbearer for a more radical, anti-EU front while Meloni leads efforts to bridge the divide between mainstream conservatives and hardliners.

"Salvini is clearly looking to radicalise his position to be constantly in the news and put Meloni in a tight spot, because she has to maintain a more establishment position," said Mattia Diletti, a politics professor at Rome's Sapienza University.

"But it is a dangerous game. How much does he want to destabilise the government or his own party?"

ELECTORAL DILEMMA

Belying his role as deputy prime minister, Salvini has appeared more like an opposition politician in recent weeks, enthus...