* Impasse paralysing government in Bosnian region
* Reflects unwieldy system of government after war
* U.S. pushing to restructure Muslim-Croat Federation
By Daria Sito-Sucic
SARAJEVO, Feb 15 (Reuters) - A court in Bosnia was asked to rule on a six-month power struggle in the country's autonomous Muslim-Croat Federation on Friday after Bosnian Muslim lawmakers blocked a motion to sack their ministers in the government.
The impasse has paralysed government in the Federation, one of two regions in Bosnia along with the Serb Republic, and is symptomatic of the complex and unwieldy system of rule in the Balkan country under the peace accords that ended its 1992-95 war.
Lawmakers from the largest Bosnian Muslim, or Bosniak, party, the SDA, blocked a confidence vote in the government, citing "vital national interest", a mechanism designed to safeguard important ethnic rights.
The move means the Federation's Constitutional Court must rule on the motion, which otherwise won the support of both houses of parliament before the SDA blocked its passage.
The dispute stems from last year, when a new coalition government was formed at the state level and tried to replicate the alliance in the Federation.
That would mean removing the SDA, which the party says would be a threat to Bosniak national interests. The opposition accused the SDA of clinging to power and the lucrative networks of patronage that come with it.
"Instead of tackling key reforms, this government has over the past two years spent money, energy and time on inter-party fighting for resources and finances," Predrag Kojovic, a lawmaker from the multi-ethnic opposition Nasa Stranka (Our Party), said during a fiery debate.
"If you had a nuclear option to keep your positions, you'd use it," he said, referring to the SDA.
The country has lurched from one political crisis to another since the end of the war, stalling reforms and leaving it trailing its fellow former Yugoslav republics in the long road to membership of the European Union.
Divided into 10 cantons, each with its own government, the autonomous Federation is a complex web of ethnic power-sharing.
Eighteen years since the war ended, the United States - the chief architect of the Dayton peace accords - launched a fresh push this year for the Federation to be restructured.
"Our experience here has been that political leaders don't do a very good job when they come together in finding solutions," U.S. Ambassador Patrick Moon told Reuters last week.
"So we are making it easy for them," he said. "We're going to do all that work for them."
It was unclear when the Constitutional Court would rule on the motion.
The court issued a statement on Thursday cautioning that it would only decide on such matters when it has a full panel of judges, after three years of arguing between political leaders over whom to appoint. (Editing by Matt Robinson; Editing by Michael Roddy)