(Bloomberg)–Turkish political debate is dominated by a single question: Will Prime Minister Recep Tayyip Erdogan, once jailed for pro-Islamist statemen’s, become president? The thought of Erdogan and his headscarved wife Emine welcoming heads of state at the presidential palace in Ankara infuriates Turkish secularists, who say he would make Turkey more like neighboring Iran. Those secularists include many members of the military, which has led three coups since 1960. Erdogan’s Justice and Development Party, known as the AKP, controls parliament. Concern that the legislature will elect him as president in May, possibly provoking a confrontation with the generals, has kept interest rates high and curbed stock prices in Turkey, an ally of the US and a candidate for European Union membership. To many, Erdogan, 53, a devout Muslim, is too divisive to head the Turkish republic, where secularism is enshrined in the constitution. In 1999, Erdogan spent four months in jail for "inciting religious hatred" after reading out a poem at a political rally that said "the mosques are our barracks, the domes our helmets, the minarets our bayonets and the faithful our soldiers." Emine, 52, has been barred from many state functions by President Ahmet Necdet Sezer, 65, a staunch secularist, because she wears an Islamic-style headscarf. Erdogan’s roots are in a pro-Islamic political party that was forced from power in 1997 amid military pressure. What’s at stake here is the political regime in Turkey," Onur Oymen, deputy head of the main opposition Republican People’s Party, said in an interview. "Erdogan’s main intention is to make Turkey a moderate Islamic state, instead of a secular country." If chosen as president for a seven-year term, Erdogan would appoint judges to the Constitutional Court and be able to veto laws passed by parliament. The assembly can override a veto by passing a law a second time unchanged. Even though Erdogan is the country’s most popular politician, only 35 percent of Turks want him to be president, according to a February poll of 2,403 people by Ankara-based research company Metropoll. Still, most investors expect him to succeed Sezer, according to a January survey commissioned by Goldman Sachs Plc. If Erdogan doesn’t run, potential candidates include Defense Minister Vecdi Gonul and State Minister Mehmet Aydin, both members of Erdogan’s party whose wives don’t wear headscarves. State Minister for Women’s Affairs Nimet Cubukcu is also a potential candidate and would be Turkey’s first woman president. Erdogan’s party says it respects secularism. "We won’t do anything that might hurt political stability in Turkey," Reha Denemec, one of the AKP’s deputy leaders, said in an interview. Erdogan has already fought with the secular establishment. In 2004, parliament approved a law making it easier for graduates of Islamic schools to enter university. It shelved the bill after the military objected and Sezer blocked it. Last year Sezer, the former head of the Constitutional Court, rejected Erdogan’s nomination of Adnan Buyukdeniz as central-bank governor. Buyukdeniz is chief executive of Albaraka Turk, a lender that follows Islamic rules barring interest rates. Party members including the speaker of parliament, Bulent Arinc, have urged changes to the constitution to lift curbs on religion, including the ban on headscarves. At the same time, the AKP has reduced the army’s influence over political decision-making, which helped Turkey win membership talks with the EU in October 2005. "The old guard in Turkey are afraid of losing their power and they don’t want to lose the presidency," said Dogu Ergil, a Turk who’s professor of politics and sociology at Uppsala University in Sweden. "While Erdogan has Islamist leanings, I think he has learned the limitations of the system. If he hasn’t, then hell will be raised."