REUTERS/Umit Bektas
Police on December 17 detained dozens of people, among them the sons of the interior minister and two other cabinet members, after months of graft probes that were kept secret from commanders who might have informed the government in advance.
The ensuing crisis is unprecedented in Erdogan's three terms, triggering the ministers' resignations and a reshuffle, and spreading speculation he may call snap elections next year.
Battered by the 10-day-old affair, the Turkish lira hit a record low, stocks were at their weakest in 17 months and the country's debt-insurance costs jumped to 18-month highs.
The market instability risked putting fissures in a showcase of Erdogan's rule, Turkey's rapid economic growth.
The affair turned more personal this week when Turkish media published what appeared to be a preliminary summons for Bilal Erdogan, one of the premier's two sons, to testify, although its authenticity could not immediately be verified.
Denying wrongdoing and portraying the case as a foreign-orchestrated conspiracy, the Erdogan government purged some 70 of the police officers involved, including the head of the force in Istanbul, and on December 21 it issued a new rule requiring police investigators share their findings with their superiors.
The Council of State, an Ankara court that adjudicates on administrative issues, blocked implementation of the regulation, a Justice Ministry official told Reuters.
GENERALS BACK JUDICIARY
Another of his feats was pruning the power of the military, once the country's dominant authority and guardian of its secularist constitution. In what implied a rebuke to Erdogan, the generals said on Friday that when they were taken to court in the past they respected the independence of the judiciary.
"The legal proceedings regarding Turkish armed forces personnel were observed in accordance with the duties and responsibilities laid out in the law," the chief of staff said in a statement.
On Thursday, a Turkish prosecutor, Muammer Akkas, said he had been removed from the corruption case and accused police of obstructing it by failing to execute his arrest warrants.
Turkey's chief prosecutor responded that Akkas was dismissed for leaking information to the media and failing to give his superiors timely updates on progress.
The government's attempts to impose new regulations on the police rile Turks who see an authoritarian streak in Erdogan and flooded the streets in mass protests this year.
The High Council of Judges and Prosecutors, a Turkish body which handles court appointments independent of the government, threw its weight behind the criticism on Thursday.
The latest requirement that police investigators keep their superiors informed amounts to "a clear breach of the principle of the separation of powers, and of the Constitution," it said.
On Friday, Erdogan fired back at the jurists.
"The High Council of Judges and Prosecutors has committed a crime," he said in a speech at Sakarya University, after receiving an honorary doctorate. "Now I ask: Who is going to try this council? If I had the authority, I'd do it right away."
Reuters could not confirm the authenticity of the putative Bilal Erdogan summons, which appeared to have come from a prosecutor's office but was unsigned.
Mass-circulation newspaper Hurriyet quoted Erdogan as saying he was the target of those naming Bilal in the case.
"If they try to hit Tayyip Erdogan through this, they will go away empty-handed. Because they know this, they're attacking the people around me," he said.
(Writing by Dan Williams; Additional reporting by Humeyra Pamuk; Editing by Louise Ireland, John Stonestreet and Giles Elgood)