SCENARIOS-Next step in Venezuelan Chavez's re-election plans

Dec 2 (Reuters) - Socialist Venezuelan President Hugo Chavez is gambling his future on a referendum to change the constitution so he can run for re-election, even though he lost a similar vote last year. Chavez's fortunes could also be influenced by falling oil prices, which would deplete the government coffers and could restrict funding for popular programs.

A referendum is expected early next year.

Here are some scenarios of what might happen:

TIMING

Chavez told his supporters to have the referendum proposal ready by February. That likely means collecting about 2.5 million signatures of support to justify a referendum. A faster, but less representative, route would be via the Chavez-dominated Congress. If 30 percent of lawmakers approve a referendum proposal, that would trigger a vote.

The electoral authority must call a vote within 30 days of accepting the referendum proposal, meaning the question will unlikely be put to the people before March.

POLITICAL TENSION

Violent street protests rocked Venezuela prior to a referendum last year, when Chavez narrowly failed to win approval for broad constitutional changes, including a measure that would allow him run for president again.

Venezuelans took to the streets against the reform, which also proposed changes to the economy that many believed would usher in Cuban-style Communism.

When it became clear that the race was tight, Chavez lashed out against a host of perceived opponents, cutting off ties with neighboring Colombia and threatening foreign companies with expulsion.

This time, Chavez will likely ask people to vote only on his re-election, but the opposition and anti-Chavez students will likely unleash a spirited campaign against him. He is likely to raise the political temperature with heated rhetoric.

HIS CHANCES

It's going to be a close race. Those who believe Chavez will win point to his robust popularity, which is close to 60 percent, and the effectiveness of his Socialist Party, which proved in November it can get out the vote better than the opposition.

But parties aligned against Chavez will be united in a campaign to block his reform. The opposition has a strong base to campaign from because it governs the most important states.

Chavez wants the referendum early, before collapsing oil prices affect average citizens in the oil-dependent nation. Any big economic shock could affect his chances.

Political scientist Daniel Hellinger, who studies the Chavez era, says: "Chavez might find it harder than he thinks to win. I'm not predicting he'll lose -- right now, I'd say the odds are in his favor. But it's no sure thing."