ANKARA, Turkey (AP) — Turkey's supreme court of appeals on Thursday overturned the convictions of 275 people, including a former military chief, who allegedly plotted to overthrow the country's Islamist-leaning government. The decision opens the way for a re-trial and their possible acquittal.

The high court on Thursday cited several flaws in the trial of ex-military chief Ilker Basbug, other military officers and lawyers, academics and journalists. They were accused of membership in an organization dubbed Ergenekon that allegedly plotted in 2003-2004 to topple Recep Tayyip Erdogan, then prime minister and now Turkey's president.

The lengthy trial contributed to the gradual erosion of the powers of the army, historically viewed as a guarantor of Turkey's founding principle of secularism.

The appeals court said the lower court had, among other flaws, failed to prove Ergenekon's existence and ruled that the defendants were denied a fair trial. It also ruled that Basbug, the former military chief, should have been tried by a high court in line with regulations on the prosecution of senior officials.

The trial, which began in 2008, grew out of an investigation into the seizure of 27 hand grenades at the home of a noncommissioned officer in Istanbul in 2007. The defendants were accused of plotting high-profile attacks that prosecutors said were aimed at sowing chaos in Turkey to prepare the way for a military coup. The lower court sentenced Basbug and 18 of the defendants to life in prison in 2013.

The Ergenekon case had polarized the country. Some saw it as an opportunity to unravel a shadowy ultranationalist and pro-secular network that allegedly acted behind the scenes with impunity, while others believed the trial was a government attempt to muzzle Erdogan's secular-minded foes and undermine Turkey's secular legacy.

The Ergenekon trial and a similar trial against other military officers helped Erdogan's government reshape Turkey's military and assert civilian control in a country that had seen three military coups since 1960.