Eight years on, and another European election campaign has been overshadowed by an act of terrorism. In 2004 it was the Madrid train bombings, just three days before the Spanish general election. Now France has felt something of the same shock, with seven people killed in three shootings in the Toulouse area — apparently by Mohammed Merah, currently (at about 1am local time) still under siege in a heavily-armed stand-off with French police.

The first round of the presidential election is still a month away, and campaigning was suspended while France came to terms with the atrocity.

But as the Madrid attacks were seen to be a game changer, delivering an unexpected victory to Spain’s socialist opposition, it’s natural to question whether Toulouse could have a comparable political impact.

Before this week, things were looking bad for incumbent centre-right president Nicolas Sarkozy. For months now, polls have consistently shown him well behind Socialist challenger François Hollande in a run-off.

Recent movement has been generally towards Sarkozy — he’s now running neck-and-neck with Hollande in the first round, and the second-round margin has come down from around 58-42 to around 55-45 (Wikipedia summarises the polls) but Hollande remains a strong favorite.

Desperate to turn things around, Sarkozy has been tacking rightwards, appealing to anti-immigrant sentiment and hoping to attract voters from the far-right National Front (more specifically, to ensure that they turn out for him in the second round instead of staying home).

Initial reactions to the Toulouse attacks suggested that this had backfired dramatically, but that was when the gunman was assumed to be driven by nativist sentiments, à la Anders Breivik. Now that he has been revealed to be a French Muslim of Algerian descent and a al-Qa’eda sympathiser, the politics look rather different.

Shades again of Madrid, where what really hurt the government was not the bombings themselves but the clumsy attempt to pin responsibility on Basque separatists, rather than admit the connection with Spain’s participation in the Iraq war. Could Hollande be similarly damaged if the public thinks the warnings of Sarkozy and the National Front’s Marine Le Pen have now been vindicated?

While the right’s prognosis certainly looks better than it did a couple of days ago, the results are unlikely to be so dramatic. For one thing, there’s a full month (plus two more weeks to the runoff) for other issues to return to centre stage. For another, none of the candidates made the mistake of trying to politicise the attacks at the start – all of them have displayed the appropriate degree of dignity, sympathy and outrage. (That hasn’t stopped a spokesman from Sarkozy’s party accusing both Hollande and Le Pen of playing politics.)

For Sarkozy it’s an obvious move, since whatever the politics of the terrorist’s motive, he can hope to get some benefit just by looking presidential.

Madrid notwithstanding, episodes of crisis tend to benefit the incumbent. But it’s not all bad for Hollande either, since his strengths are seen as those of a moderate and a conciliator, a safe pair of hands.

Le Pen will be looking at the issue as her one faint opportunity to break into the second round, as her father famously did in 2002. But the gap seems too big to make up; the polls put her at least ten points behind Hollande and Sarkozy. Centrist François Bayrou, who managed 18.6% in 2007, is well back in fourth place (just ahead of the far left’s Jean-Luc Mélenchon), and after this week it seems France is even less likely to want to hear his message of liberal tolerance.

For the European Left, this is an absolutely vital election; its big chance to get back into the game. If Sarkozy were to somehow manage a comeback, on top of the left’s series of defeats in the last two years, it would be a huge psychological blow.

Odds are that even Islamic terrorism won’t do it for him. But don’t write him off just yet.