With the threat of arrest hanging over him and his party restricted by ZANU PF, Zimbabwe’s opposition leader, Morgan Tsvangirai, faces his sternest leadership test since entering the coalition government with President Robert Mugabe.

Tsvangirai’s party chairperson, Lovemore Moyo, has been ousted from the key post of speaker of Parliament by a court ruling; six of his MPs, including a senior minister, face various charges; and Zanu-PF is pressing for his arrest on contempt of court charges.

Showing his frustration, Tsvangirai left the country to meet regional leaders, hoping to press them to step in. But this has not eased the pressure on him, even from within his party. There is increasing internal frustration that Mugabe has been running rings around the Movement for Democratic Change, which has failed to come up with any real strategy to push back a resurgent ZANU PF, which wants Tsvangirai arrested for his angry reaction to a Supreme Court ruling cancelling the election of Moyo as speaker, a powerful post both parties crave.

The court ruled that Moyo’s election was flawed because some MDC MPs had shown their ballots to party leaders before casting their votes. Because the race had been so close in that poll, the MDC leaders had opted not to take any chances and wanted to make sure that their members voted for their candidate.

The court ruled that this made the vote “null and void”. Following the ruling, Tsvangirai told reporters that the decision showed the judiciary was “a willing appendage of ZANU PF” and that his party would “not accept the decisions of some ZANU PF politicians masquerading as judges”. Mugabe’s party, he charged, was trying to use the courts “to subvert and regain what it lost in an election”.

Indeed, having lost control of Parliament for the first time in 2008, ZANU PF is clawing its way back. Now Tsvangirai will need to muster all his political skills to steer his party around the vote, regain control of the legislature and push ZANU PF back.

Mugabe’s party has increasingly set the agenda, managing to push to centre stage its twin central issues of Western sanctions and empowerment and completely drowning out the MDC’s reform agenda. The battle may escalate next Tuesday when Parliament is likely to sit to elect a new speaker. To win, Tsvangirai will have to negotiate with MPs from both ZANU PF and from the smaller MDC faction. Both these groups are bitterly opposed to Tsvangirai and he faces the tough job of cutting deals with them.

ZANU PF and the main MDC have 96 seats each, but the MDC may well have its numbers whittled down if the arrest of MPs continues. With eight votes, the smaller MDC may hold the balance of power. However, there’s no telling where those votes would go, with the faction split down the middle over a power struggle between party leader Welshman Ncube and Deputy Prime Minister Arthur Mutambara.

Lovemore Moyo will not be allowed to vote, Parliament clerk Austin Zvoma said this week. The case against the speaker was brought to court by Jonathan Moyo, who joined ZANU PF in 2009 again after leaving it to stand as an independent in the 2008 election. Since his return to ZANU PF, where he has been given a seat in Mugabe’s politburo, Moyo has increasingly driven the party’s strategy.

This week he stepped up pressure on the country’s attorney general, Johannes Tomana, a Mugabe ally, to arrest Tsvangirai and Lovemore Moyo for their criticism of the judges. “What now needs to be done is to teach him and Tsvangirai that they are not above the law and that they are prosecutable,” Moyo was quoted as saying on Wednesday. “There is no better way of teaching them that lesson than hauling them before the same court that they have held in contempt.”