The Staggers 21 April 2017 The French terror attack could benefit Marine Le Pen A run-off between Le Pen and a scandal-ridden François Fillon suddenly looks worryingly plausible. Getty Images. Sign UpGet the New Statesman's Morning Call email. Sign-up Good morning. Here in Britain, the election campaign rumbles on, but has been thrown into sharp relief by a terrorist attack which killed a policeman and left two injured, on Champs-Élysées, for which Islamic State have claimed responsibility. The attacker was shot by police. The major presidential campaigns have suspended their campaigns for a day as a mark of respect. But inevitably, the question will be asked: what impact will this have on the campaign? A consistent pattern of French politics in recent times has been that high-profile acts of criminality have boosted Marine Le Pen by a few points in the polls. That goes not only for terror attacks by jihadists but terror attacks by far-right activists, too, as well as heists and riots. The big question is whether those jumps are caused by differential abstention in polling respondents - that is, a high-profile crime occurs, National Front supporters get excited and the rest decline to answer polls - or if the effect has real world implications. If the latter is the case, that means that Le Pen's recent slide in the polls may be reversed when France votes in the first round on Sunday, getting her through to the run-off. But the more important thing may be what it does to the identity of her rival. François Fillon, of the mainstream right, has also tended to benefit in the polls after these incidents. That Closer is reporting that he had an affair with an aide may finally dent his support with conservative Catholics, whose votes are keeping him in contention. But if not, a run-off between Marine Le Pen and a scandal-ridden François Fillon - the weakest opponent of the three she could face according to the polls - suddenly looks worryingly plausible. › Robert Webb: Prince Harry was right to speak about his mental health. No one should "man up" Stephen Bush is political editor of the New Statesman. His daily briefing, Morning Call, provides a quick and essential guide to domestic and global politics. Subscribe To stay on top of global affairs and enjoy even more international coverage subscribe for just £1 per month!