FACTBOX: What's next in Zimbabwe's political crisis?

(Reuters) - Zimbabwe's main opposition Movement for Democratic Change (MDC) party won the vote for parliament speaker on Monday, dealing a blow to President Robert Mugabe in a post-election power struggle.

But Zimbabwe's balance of power remains delicate.

Here are some questions and answers on Zimbabwe's political uncertainty.

WHAT IS THE BALANCE OF POWER?

ZANU-PF won a later vote for the presidency of the upper house of parliament, the Senate -- where it has a majority -- meaning it can block legislation passed by parliament.

The MDC, with support from MPs of a breakaway faction, can pass some bills in the lower house but these can be blocked in the Senate.

HOW WILL THE MDC BENEFIT?

The election of the MDC's Lovemore Moyo to Speaker of the Lower House of Assembly -- one of the most post powerful positions in Zimbabwean politics -- will strengthen party leader Morgan Tsvangirai's position in deadlocked power-sharing talks.

WHAT'S MUGABE'S NEXT MOVE

Mugabe is due to open parliament on Tuesday, and is expected to name a new cabinet this week although he may leave some slots -- already agreed with the opposition -- for both Tsvangirai and the breakaway MDC faction led by Arthur Mutambara.

WHERE DO POWER-SHARING TALKS STAND?

Analysts say Mugabe is unlikely to give in to Tsvangirai's demands for more executive powers but officials from both sides are expected to resume efforts to break the stalemate this week.

CAN REGIONAL POWERS SECURE A BREAKTHROUGH?

South African President Thabo Mbeki, the main mediators in the Zimbabwe talks, and some other regional leaders are expected to press on with behind-the-scenes talks aimed at reaching a settlement.

Analysts say most of the them blame Tsvangirai for the deadlock, easing pressure on Mugabe.

WHAT CARDS DOES TSVANGIRAI HAVE?

Although regional leaders are leaning on Tsvangirai to do a deal, Western powers have made clear they want him to have a strong executive role in a power-sharing government.

Any attempt to form a government without him could lack widespread recognition and fail to win the funding needed to revive the crippled economy.

HOW INFLUENTIAL IS MUTAMBARA?

Mutambara has emerged as a possible kingmaker.

Mugabe's party lost control of parliament in March elections for the first time since independence from Britain, gaining 99 seats, but Tsvangirai's party only got 100 seats so does not have an absolute majority either.

That leaves control in the hands of Mutambara's breakaway wing of the MDC, which has 10 seats. There is one independent.

But Mutambara faces dissent in his own MDC breakaway faction.

A silent revolt by MPs representing the faction -- who are believed to have voted for Tsvangirai's candidate for speaker in a secret ballot -- has undermined and could scuttle ZANU-PF plans for cooperation or a power-sharing deal with Mutambara's group.

(Reporting by Cris Chinaka; Editing by Matthew Tostevin)