France's Socialist President Francois Hollande is engaged in the biggest test of his presidency, facing months of protests and strikes against a labor law that are threatening nationwide fuel shortages.

The fight is over a reform that aims to boost hiring by making France's 35-hour workweek more flexible, making it easier to fire workers and weakening unions' powers. Some labor groups say the measures will erode workers' hard-won protections and mainly benefit big businesses.

Here are some possible outcomes for the intensifying standoff.

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STRIKES COULD GROW, HURT ECONOMY

Seven unions and student organizations have called for a nationwide day of protests and strikes on Thursday, in addition to blockades of fuel depots and refineries since last week.

Strikers could be joined by employees of nuclear plants, which provide most French electricity. In addition, new calls for strikes in the rail sector should disrupt national and regional traffic.

Since numerous street demonstrations across France in recent weeks didn't lead to the withdrawal of the law, unions are now trying to boost mobilization.

They hope to put stronger pressure on the government ahead of the June 10-July 10 Euro 2016 soccer championship, set to draw attention from millions of supporter all over Europe.

They also want to use the leverage of potential damage to French economy to force the government to change its mind.

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LABOR LAW COULD BE SCRAPPED OR TWEAKED

Hollande insisted last week he won't give up. Despite record-high unpopularity rates, Hollande hopes to run again for presidency next year and needs to be able to say he has implemented reforms during his first term.

He also considers the law has been sufficiently negotiated with unions and employers organizations earlier this year.

But there's plenty of precedent for government surrender on reform. In 2006, the conservative government passed a law at parliament to create a new job contract specific for young people, but was forced to with withdraw it few weeks later by major youth protests. And massive labor action in 1995 forced another conservative government to abandon pension reforms.

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PROTESTS COULD LOSE MOMENTUM

The government is focusing on unblocking roads — through police intervention — to allow trucks to get access to fuel depots and be able to supply gas stations.

In 2010, former president Nicolas Sarkozy used a requisition order — allowed under very strict rules — to counter a similar strike in refineries against a plan to raise the retirement age from 60 to 62. The reform finally passed.

The government is also counting on a potential growing unpopularity of the protest movement in the French public opinion that would weaken unions opposed to the law.

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UNIONS FALLING INTO DISARRAY

Protesters are protected by the right to strike, entrenched in the preamble of the French Constitution. But not all unions agree with the strikes and protests.

The strongly leftist CGT (Confederation generale du travail), the main French union, is leading the protest movement. Yet, other major unions agreed earlier this year to negotiate with the government and consider they obtained significant changes in the reform.

The labor law has crystallized the struggle for power between some unions considered as reformers and others that believe protests and strikes offer better leverage to defend employees' rights.

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PARLIAMENT WILD CARD

The government forced the bill through the lower house without a vote because of divisions within the Socialist majority, and it goes to the Senate from June 13 to June 24. The conservative house is expected to change the law to give it a more right-wing perspective.

Yet the lower house has the final say, meaning the law will then have to be discussed again at the National Assembly, probably in late June or early July.

The government might have to use again its special power to pass the law without a vote — which may prompt renewed protests, strikes or other labor action.