ANKARA (Reuters) -A Turkish court will decide on Monday whether to oust the head of the main opposition, in what some see as a test of the country's shaky balance between democracy and autocracy after a nearly year-long legal crackdown on the party. Hundreds of members of the Republican People's Party (CHP) have been jailed pending trial in a sprawling probe into alleged corruption and terrorism links, among them President Tayyip Erdogan's main political rival - Istanbul Mayor Ekrem Imamoglu. The unprecedented crackdown, which has eroded the CHP's leadership ranks, has also sharpened concerns over what critics call Turkey's autocratic slide in which the courts, media, military, central bank and other formerly more independent institutions have bent to Erdogan's will over his 22-year reign.