ISTANBUL — Even before President Recep Tayyip Erdogan of Turkey was inaugurated last week, he began elbowing his way into the front ranks of the globe’s strongmen.
Hours before taking the oath of office — after 15 years already in power — Mr. Erdogan published a 143-page decree changing the way almost every government department and public body in the country operates.
In the days since, he has issued several equally lengthy decrees and presidential decisions, centralizing power and giving him the ability exert control in nearly all areas of life with almost unchecked authority.
At a moment when democratic systems around the world are under increasing pressure, Mr. Erdogan, who was re-elected in June, is among those leaders, like Vladimir V. Putin of Russia and Viktor Orban of Hungary, who are using the levers of democracy to vastly expand their authority.
Among the changes Mr. Erdogan has put in place under the new presidential system are these:
• The prime minister’s office has been abolished;
• The military has been brought under firmer civilian control;
• The president will draft the budget, choose judges and many top officials;
• The president can dismiss Parliament and call new elections at will;
• The president appoints the head of the National Intelligence Agency, the Religious Affairs Directorate and the Central Bank, as well as ambassadors, governors and university rectors, among other top bureaucrats;
• Virtually none of the president’s appointments require a confirmation process.
None of the amendments Mr. Erdogan decreed were subject to public debate before becoming law. The vast accumulation of power fulfills Turkey’s shift from a parliamentary system to the presidential one that was narrowly approved by voters in a referendum last year.
The voluminous decrees, analysts say, promise months of administrative upheaval as agencies are abolished and government employees reassigned.
Critics have voiced concern at the lack of checks on the president’s increased powers.
“The state is being reorganized around Tayyip Erdogan,” the columnist Asli Aydintasbas wrote in the secular opposition newspaper Cumhuriyet last week.
Many of the changes, analysts point out, merely formalize what was already the case: It is Mr. Erdogan who makes the decisions. But the consolidation of his power is far-reaching.
Mr. Erdogan has also amended the counterterrorism law in expectation of lifting the state of emergency, which expires on Thursday and was put in place two years ago after a failed military coup against him.
The new measures bring the powerful Turkish military firmly under civilian control — a step that the president says is in line with changes required under the European Union’s accession process. The bloc has dangled admission before Turkey for years.
But Mr. Erdogan and his fellow Islamists have long called for a presidential system and for greater civilian control over the military. Turkey’s recent history has been filled with military coups, and the Islamists chafed more than others under military rule.
Mr. Erdogan has placed the chief of staff of the armed forces under control of the Defense Ministry, and the Supreme Military Council, which decides senior appointments in the armed forces, has been reconfigured to include more civilian ministers than military commanders.
Mr. Erdogan appointed a loyalist, the former chief of staff, Gen. Hulusi Akar, as his first defense minister under the new system. General Akar opposed the 2016 coup — he was taken prisoner on the night of the failed coup by rogue officers — and has overseen a comprehensive purge of the armed forces in the two years since.
“It seems Erdogan has planned the transition to be as smooth as possible by naming Akar, Turkey’s top soldier, as the defense minister,” the columnist Murat Yetkin wrote in The Hurriyet Daily News.
Mr. Erdogan outlined his own powers in one new decree after his inauguration. He will appoint the chief of staff of the armed forces — along with the commanders of the land, air and naval forces and the deputy chief of staff — by presidential decision, which needs no confirmation process. The president will also make promotions in the upper ranks of the security forces from colonel upward.
Decree 703, issued just before Mr. Erdogan was sworn in to his new term, also removed many of the regulations in the selection process for appointments.
For instance, the president will appoint the rectors of Turkey’s public and private universities, without the usual shortlisting procedure by the university and Higher Education Board.
“Yes, U.S. President Trump can appoint a replacement to a vacant seat in the Supreme Court, but he does not appoint a police chief in Massachusetts or a public theater director in Boston,” Ms. Aydintasbas commented in Cumhuriyet. “He cannot appoint a state governor or even a university rector,” she added.
The decree also lowers the qualifications for judges appointed to the government’s administrative courts, which regulate government departments. Previously, judges had to hold law or political science degrees, but they can now be drawn from any degree program, as the Justice Ministry sees fit.
One of Mr. Erdogan’s most controversial moves has been the appointment of his son-in-law Berat Albayrak as minister of the newly combined Treasury and Finance Ministry.
A presidential circular published in the Official Gazette over the weekend also placed the Central Bank under the responsibility of the ministry.
Mr. Erdogan has emphasized that changes are needed to make state institutions more responsive and efficient. But the latest regulations diminish the legal and practical independence of the Central Bank, Umit Akcay, an associate professor of Economics at the Berlin School of Economics and Law, said in emailed comments.
Turkish equities and the country’s currency fell in value in the days after Mr. Erdogan’s appointment of a new cabinet that removed two highly regarded officials — Deputy Prime Minister Mehmet Simsek and Finance Minister Naci Agbal — and that promoted Mr. Albayrak.
Mr. Albayrak addressed the changes at the Central Bank last week in an effort to calm the markets.
“The policy in the new period aims to render the Central Bank more effective than ever,” he said at a news briefing last week. The Central Bank’s decisions will be driven by market conditions, he said, promising “a more predictable, simple and determined monetary policy in line with the objectives.”
Yet Mr. Albayrak’s appointment is part of the concern unsettling investors, the credit ratings service Moody’s said in a statement the same day. “Such appointments will inevitably raise questions regarding the independence and experience of Mr. Erdogan’s government,” Moody’s said.
Ms. Aydintasbas warned that centralizing power had never worked in Turkey.
“I believe that such concentration of power will tire Turkey out, lock out the state and overload the economy,” she said. “I hope I’m mistaken.”