Once again, France woke to news of a string of dawn raids against suspected Islamists across the country, from the old industrial heartlands of the north to Marseille on the southern coast. Days earlier, rolling TV-news and breakfast bulletins broadcast dramatic images as elite anti-terrorist squads in black body armour smashed windows and bashed down doors shouting "Police!", emerging with hand-cuffed suspects with their faces covered, on residential streets from Nantes to Toulouse.

Less than three weeks before the first round of the presidential election, France is gripped by one of its biggest crackdowns on suspected radical Islamists in recent memory. Amplified by TV coverage, it has been led by an unrelenting Nicolas Sarkozy, who is also battling for re-election. Opposition politicians now openly question whether the timing and TV crews are as much linked to electioneering as anti-terrorist crime prevention.

France is still in a state of shock and confusion after Mohamed Merah, a 23-year-old unemployed panelbeater from Toulouse, went on a 10-day killing spree across south-west France, executing three paratroopers and shooting children and a rabbi at the gates of a Jewish school. Following a dramatic 32-hour siege at his flat, Merah died in a hail of police bullets as he leapt from the balcony. But questions remain over how Merah – who claimed inspiration from al-Qaida, was heavily armed, on police intelligence files and had been under surveillance – was not picked up earlier and his attacks prevented. Some commentators warn that the new anti-terrorist crackdown, which included the deportation of a handful of preachers, should not be used as a smokescreen to distract from potential failings in the Merah operation.

The right-wing Sarkozy had long ago seen his election strategy compared to that of his friend George W Bush's 2004 fight for re-election in the US: styling himself as the only trustworthy protector of the nation in the face of serious threat. A month ago, the danger was impending financial meltdown. Now, it is closer to Bush's own target: Islamist fundamentalism and terrorism. Sarkozy last week likened the Toulouse killings to France's 9/11. The scale of the attacks maybe different, he said, but the national "traumatism" was the same.

The justice system will have the last word on the arrests, which were not directly linked to Merah. Preliminary charges have been filed against 13 alleged members of a banned fundamentalist group. An intelligence chief suggested militants were planning a kidnapping. The 10 arrested on Wednesday were suspected of links to Islamist websites and of threatening violence in online forums.

But in an election more than ever determined by TV coverage, Sarkozy's opponents queried the "spectacle" of the raids and their timing in the wake of the Toulouse killings. "I'm not questioning all that's being done. I'm simply saying that we should have perhaps done more before," said François Hollande, the Socialist candidate. The government insists the arrests had nothing to do with the elections, but with the security and protection of France.

The "Toulouse effect" on the presidential race has so far been limited. Crucially, it allowed Sarkozy, during a week of national mourning, to regain presidential stature. Before Toulouse, he had been heckled so badly on the campaign trail in the Basque country that he took refuge in a bar. Now, over 70% of French people approve his stance at the time of the Toulouse killings. His poll ratings have lifted giving him a narrow lead in the first-round, but Hollande remains ahead in the final 6 May run-off.

Yet the shootings have not changed French voters' chief topics of concern: crippling unemployment and the difficulty making ends meet. Crime and terrorism remain low on their list. Indeed, many French people feel disappointed that the presidential debate isn't addressing their everyday worries, and abstentionism could be high. But the extreme-right Front National's Marine Le Pen has used Toulouse to hammer home her rhetoric on fears about Islam, terrorism, immigration and what she warned were fundamentalists festering on France's notorious suburban high-rise estates (even if the raids were often carried out on smart semi-detached houses). To win the election, Sarkozy knows he must court Le Pen's voters. Politicians and religious leaders, have warned against stigmatising French Muslims – a long-held fear following Sarkozy's recent Front National-inspired election crusade against halal meat.