PARIS ― Five days before the first round of the French presidential election, the threat of terrorism has returned to center stage in the campaign for the Elysee.

There has been no lack of news on the topic in Europe. Between the November 2015 attack in Paris and the July 2016 attack in Nice, as well as the recent events in London and Stockholm, terrorism has been a core issue. Yet, despite its prominence in the media and public debate, the subject had been virtually absent during the campaign so far.

Presidential candidate Francois Fillon said Tuesday at a campaign event in Lille, “There is a topic that has been left out during this campaign, even though it is dramatically making itself known: It is terrorism.”

The silence ended dramatically Tuesday when authorities announced the arrest of two young men in the port city of Marseille. Police found guns and bomb materials after arresting the men and said the duo had planned a violent attack ahead of Sunday’s vote.

Philippe Laurenson / Reuters French firefighters block the street as police conduct an investigation after two men were arrested in Marseille on April 18. Police say the men planned a "violent attack" before the eleciton.

Terrorism was pushed to the background of the campaign amid the various scandals surrounding two of the presidential candidates, conservative Fillon and far-right leader Marine Le Pen. Both candidates share muscular national security views, but their legal challenges shifted much of the debate to the morality of politicians and how the legal cases would affect the candidates.

In fact, the candidates hadn’t appeared particularly worried about security at their own campaign events. Earlier this month, a protester managed to pelt Fillon with flour in Strasbourg, while centrist front-runner Emmanuel Macron was egged during his visit to the Salon of Agriculture. On Sunday, a member of the feminist protest group Femen rushed the stage as Le Pen spoke, even though her security service had been warned of the risk. Far-left candidate Jean-Luc Mélenchon has been holding large open-air rallies, even though it’s difficult to ensure security at those events.

But the discovery of the Marseille plot had practical repercussions. Security has been stepped up significantly. Authorities said they are working with the four campaigns and deploying specialized services. During a recent visit by Fillon to Montpellier, snipers and elite police officers helped guard the area.

Robert Pratta / Reuters Marine Le Pen, the French National Front candidate for president, at a rally in Marseille on April 19.

In addition to sparking practical changes, the foiled plot in Marseille also had political consequences. While Fillon said after the arrests that “democracy must not bow to the threats and intimidations of terrorists,” his camp has clearly been tempted to capitalize on the event.

Amid rumors that Fillon was the target of the plot, Lydia Guirous, a former spokeswoman for Fillon’s party, tweeted: ”The two suspects were planning to attack Francois Fillon. The barbarians know who is most determined to fight against Islamic totalitarianism.”

On the side of the National Front, Le Pen has doubled down on her anti-immigration stance in the wake of the incident. She also hasn’t shied away from insinuating she might have been under threat as well. “The fact that the two individuals were arrested in Marseille while Le Pen was holding a meeting there the next day is perhaps not a coincidence,” a spokesman told Agence France-Presse.

Le Pen issued a very tough statement in reaction to these arrests. “In the last two five-year periods, Islamist fundamentalism has exponentially developed in France without any response ever being made. The result is a devastating multiplication of attacks and threats of attacks,” Le Pen said in a statement Tuesday.