PARIS (AP) — As France's prime minister when terrorists killed 130 people in Paris in 2015, Manuel Valls was on the front line of the government's response, calling the attack an act of war and successfully lobbying parliament for emergency powers.

Just 14 months later, having stepped down in December from President Francois Hollande's government, Valls' political future has never been more uncertain.

Should he fail to secure the Socialist Party's nomination for France's two-round presidential election in April and May, Valls could be staring at a long spell in the political wilderness.

This weekend's first round of voting in the Socialist primary pits the Spanish-born 54-year-old, who became French at 20, against six other candidates. With little to separate them politically, Valls' opponents have tried to set themselves apart by attacking him.

Valls, in return, argues that his years spent at Hollande's side, first as France's top cop at the interior ministry and then as prime minister, have armed him with the experience that France's next leader will need as the country battles Islamic terror and other challenges.

"In this difficult world, with my convictions, my ability to speak the truth, I assumed the responsibilities," Valls told the Liberation newspaper. "I take responsibility for has been done."

But his association with Hollande, who gave up on a second presidential term that he had no hope of winning, and Valls' own record in government make his candidacy a tough sell.

Voters could use Sunday's primary to punish Valls for pro-business reforms and a 40-million-euro ($42 million) tax cut for companies that he pushed through when he was prime minister. On six occasions, Valls forced new economic and labor laws through parliament without a vote, infuriating lawmakers.

Valls now says that as president, he would limit this extraordinary power — an about-face that leaves him open to accusations of hypocrisy. Several of his opponents in the primary are vowing to repeal the labor measures that sparked wide protests, on grounds that their passage was undemocratic.

On the campaign trail, Valls has encountered problems, too.

In the western region of Brittany, a young man lightly slapped Valls as he was shaking hands with a small crowd, and was immediately wrestled to the ground. Last month, a man threw flour at Valls during a visit to the eastern city of Strasbourg.

The outcome of Sunday's primary is uncertain, with Valls seemingly locked in a close race with two other former ministers of Hollande's — Benoit Hamon and Arnaud Montebourg.

Unlike Valls, neither carries the baggage of close ties with Hollande's presidency. They rebelled in 2014, stepping down as ministers amid feuding over economic policy. Valls, on the other hand, split with Hollande only when it became clear even to the president that he was too unpopular to run again.

Hamon, 49, a former junior minister and education minister, is pledging to push for the introduction of a modest but regular "universal income" living allowance for all French citizens. Montebourg, 54, a former industry and economy minister, wants protectionist measures and state intervention to boost the French economy.

The four other candidates — Vincent Peillon, Francois de Rugy, Sylvia Pinel and Jean-Luc Bennahmias — aren't expected to be among the top two who will advance to a Jan. 29 runoff.

For the winner of the primary, the road will get even steeper.

The Socialists are being squeezed on both sides by leftist leader Jean-Luc Melenchon and Hollande's former economics minister, Emmanuel Macron, running as an independent. Both are attracting crowds and headlines.

The fear for the Socialist presidential candidate in the first round of balloting in April will be that Melenchon and Macron siphon off so many voters that conservative candidate Francois Fillon and far-right National Front leader Marine Le Pen get a clear path to the French presidential runoff in May.

Manuel Valls

France’s ex-PM Valls fights for spot in presidential primary