Turkish lawmakers are expected to approve the scrapping of a ban on Islamic headscarves at universities on Saturday but a mass rally the same day will show the depth of public opposition to the move.
The protest, organised by more than 70 trade unions and non-governmental organisations, will take place at a public square about two kilometers (a mile) from the parliament complex, two hours after lawmakers convene at 0900 GMT.
It will be the second large-scale demonstration against easing the ban - imposed after a 1980 military coup - after a February 2 protest that drew more than 125,000 people.
Parliament is all but certain to approve the constitutional amendments, tabled by the ruling Justice and Development Party (AKP) and backed by a far-right opposition party, the Nationalist Action Party. In a first-round vote on Thursday, the package garnered 404 'yes' votes in the 550-seat parliament, well above the 367 votes required to amend the constitution.
But the reform has angered secularists - among them the army, the judiciary and academics - who see the headscarf as a symbol of defiance against the strict separation of state and religion in the mainly Muslim country.
They say lifting the ban will put pressure on women to cover up, pave the way for the lifting of a similar ban in high schools and government offices, thus eroding secularism and ushering in religious rule.
"The headscarf issue is in essence the issue of protecting the principle of secularism enshrined in the constitution or renouncing it," the organisers of Saturday's rally said in a statement. The judiciary also sounded a warning.
"Of course, it is the parliament's primary and natural duty to make legal and constitutional amendments, but its authority should not be used to weaken secularism," Hasan Gerceker, the newly-elected head of the Supreme Appeals Court, said Thursday.
The strictly secular Republican People's Party has already threatened to challenge the reform at the constitutional court once it is adopted. The AKP, largely distrusted by secularists for its roots in a banned Islamist party, rejects charges that it has a plan to undermine secularism and says the ban violates freedom of conscience and the right to education.
The package amends the constitution to read that the state will treat everyone equally when it provides services such as university courses, and that no one can be barred from education for reasons not clearly laid down by law.
But some analysts, among them those who favour the lifting of the headscarf ban, say the amendments have been prepared too hastily and accuse the government of insincerity for focusing on an explosive problem rather than drawing a plan to remove all obstacles to women's education.
According to a 2004 study by the influential Istanbul-based think-tank TESEV, the headscarf ban is ranked last among the reasons preventing women from going to university.
The ban affected only about one percent of the 1,557 women polled, it said. Once adopted in parliament, the constitutional amendments will have to be approved by President Abdullah Gul, who was an AKP party member before being elected president last year. He has yet to veto any government-sponsored law. The AKP then plans to amend the higher education law to bring it in line with the constitution.