Turkey's ruling AK party is facing the prospect of closure, after the country's Constitutional Court agreed to hear a case accusing it of undermining secularism. The prime minister and president also face a five-year political ban. The case, as Dorian Jones reports from Istanbul, has plunged the country into a political crisis.

Constitutional Court Deputy Chairman Court Osman Paksut announced the high court would hear the case against the ruling Justice and Development Party.

The AK party, as it is known in Turkey, is accused of undermining the secular state. If the prosecutor wins the case, Prime Minister Recep Tayyip Erdogan and President Abdullah Gul along with 69 other members of the ruling party face a five-year political ban.

In last year's general election, the party with Islamic roots won nearly two-thirds of the seats in parliament with 47 percent of the vote.

Some political observers say that following his recent victory, Prime Minister Erdogan abandoned the conciliatory approach to the divisive issue of religion, which characterized his previous administration.

"With that 47 percent, he thinks he can rule the world," said Ppolitical columnist Murat Yetkin.

On the other hand, some political scientists, like Soli Ozel, accuse the secularists of mounting an attack on Turkish democracy. "In political terms there is no question of one of the last struggles of the truly corroded established orders, which sees this country as their own patrimony... And looking at their mindset, I am afraid they are so closed to the rest of the world and what goes on in the world, and what Turkey actually means to the rest of the world, that they push for the closing of the party and then we will be in for a long period of turbulence."

The case has put the issue of religion in public life front and center, and is already dividing the country.

On the streets of Istanbul there are strong views on both sides. "... The general people does not think Turkey has to be a Muslim, religious country. Turkey has to be a republican country," said one person.

But a shopkeeper disagrees, saying the closure case is bad for Turkey and that, God willing, it will not happen.

The parliament's election of President Gul, who was a prominent member of Islamist parties, last year polarized the country and laid the foundation for the current crisis, according to analyst and government adviser Nuray Mert.

"The whole atmosphere was changed with the nomination. Why? Because he was seen as a figure of challenge for the republican ideology, with a wife with a headscarf, at the same time coming from the leadership of the ex-Islamist party, ex-Islamist movement. He tried to re-invent himself as a neutral politician, nothing to do with Islamist past, but it did not work at the end."

Mr. Gul has a made a record number of appointments to key positions, fueling fears among secularists that the AK party is seeking to sabotage the secular principles of the state.

Some local authorities controlled by the AK have sought to restrict the sale of alcohol, seen as an important right linked to the secular identity of the country.

But it was parliament's decision to ease the ban on religious headscarves in universities that, observers say, triggered the court case. The case is expected to last several months.

Prime Minister Erdogan has indicated he may try to change the constitution to block the case, although opposition parties are against such a move.

Mr. Erdogan has enough votes in parliament to put a constitutional change to a national referendum, but most observers warn that such a vote risks further polarizing the country.

Mert says that is a real danger. "If they are ready to fight with each other by all means, this is frightening, if both parties see the situation as a dead end, a point of no return, and the crisis will deepen and it will be even more difficult to foresee the outcome."

Turkey is no stranger to such a crisis. In 1998, the AK party's predecessor, the Welfare Party, then the country's largest party, was also closed down on similar charges. The case was upheld by the European Court of Human Rights.

Ozel says that experience may offer hope. "... One net result was to allow the Islamist movement to break and to allow the new generation with a more open ideological framework to actually start the new party and move on."

If the AK party is shut down and its leadership banned, the party can reform itself and change its name, but analysts question whether Turkish society will be able to heal as easily.