France’s Marine Le Pen faces a make-or-break moment on Monday, as a judge rules on whether she should be banned from the next presidential election.

The hard-right leader, who is ahead of all her rivals in the 2027 race, will be in court at 10:00 local time (09:00 BST) for the verdict of a party-funding trial targeting her National Rally (RN) party.

At the trial’s conclusion in November, the state prosecutor demanded guilty verdicts for Le Pen and 24 others accused of using EU parliamentary money to pay party salaries.

But to general surprise the prosecutor also said that Le Pen’s punishment should be not just a €300,000 (£250,000) fine and prison term, but also ineligibility from running for public office for five years.

Crucially, he said the ineligibility should kick in straightaway – and not be suspended pending the appeal that Marine Le Pen is expected to file if convicted.

The three judges are not obliged to follow the prosecutor’s recommendations.

But if they do, it would mean Le Pen, who is 56, being barred from standing in a presidential election in which she is tipped as a potential winner.

“It’s my political death they are after,” she said in November.

Many French commentators – and not only those who support Le Pen – have warned of grave consequences for democracy if the judiciary is seen as interfering in the choice of the country’s leader.

“The justice system has the fate of Marine Le Pen in its hands… For her to be convicted for any wrong-doing is perfectly normal. But stopping her from running in the presidential [election] – that’s another matter entirely,” wrote veteran analyst Franz-Olivier Giesbert in the centre-right Le Point magazine.

“Is it not hazardous – not to say perilous – to give to judges the task of determining whether this or that candidate has the capacity to run for office?” said Bruno Jeudi, editor of La Tribune Dimanche newspaper on Sunday.

Marine Le Pen told the same newspaper: “Personally I’m not nervous. But I can see why people think I might be. The judges have the power of life or death over the movement. But I don’t think they will go so far as to do it.”

Various scenarios for the verdict are under scrutiny.

First, Le Pen could be cleared of blame in the EU parliamentary money affair. This is widely seen as unlikely.

Second, the judges could convict her but make the ineligibility not automatic. In that case, she would immediately appeal and the ineligibility would not apply until after a second trial (and conceivably a third to the high court of appeal).

That would leave her free to run in 2027, though with the handicap of a conviction for misuse of public money. However it is far from clear that a conviction would do her cause much damage, given the series of party funding scandals that have affected all French parties over the years.

Third, the judges could follow the prosecutor and order automatic ineligibility. In this case she would appeal, and the other parts of the sentence (fine and prison) would be suspended. However she would be unable to run in 2027.

Fourth, the court could give her a shorter term of automatic ineligibility – say one year – making it theoretically possible for her to run.

2027 would be Marine Le Pen’s fourth presidential race, and the one offering the greatest chance of victory.

A poll in the right-wing newspaper JDD Sunday gave her between 34-37% of the first round vote, well ahead of any of her possible rivals.

In the last two presidentials, she fell foul of the two-round system which allowed opponents of left, centre and right to rally behind a single candidate – Emmanuel Macron – to keep her from power.

But years of “detoxification” after she eclipsed her father Jean-Marie Le Pen at the head of the party have made the anti-RN vote far less cohesive than it used to be, while victories for the hard-right in other countries have helped lift the taboo of an RN government.

If Le Pen is barred from running, her logical replacement would be Jordan Bardella, the 29-year-old party president who was being groomed to be her eventual prime minister.

However party insiders admit there has been little internal preparation for what would be widely seen as a huge and destabilising political earthquake.

One result of Le Pen being declared unable to run in 2027 could be to weaken still further the minority French government of Prime Minister François Bayrou. With 120 members in the National Assembly, the RN has the power to vote with the left in a vote of no-confidence to bring the government down.

Until now, Marine Le Pen has held back her troops. She might feel less inclined to, if she feels she has been the victim of an establishment stitch-up.