Turkey's parliament has given initial approval to electoral reforms brought by the ruling party amid a crisis over the country's secular traditions.
Opposition seats were empty for Sunday's failed vote
Among other measures, the ruling AK party, which has Islamist roots, wants the president to be elected by the people, rather than by MPs.
The package passed a first round but must now be debated again.
The crisis arose when the secular opposition blocked the presidency bid of the AK party's candidate.
The parties say Foreign Minister Abdullah Gul has an Islamist agenda.
A second attempt to elect Mr Gul failed in parliament on Sunday.
The government last week called early elections for July in an attempt to resolve the row.
The AK party is trying to push through the constitutional change before parliament's dissolution.
2 May: Ruling party requests early elections
6 May: Re-run of parliamentary election for president
16 May: President Ahmet Necdet Sezer's term ends
22 July: Likely date for early general election (currently set for November)
It has secured the support of a small centre-right party but needs a two-thirds majority to amend the constitution.
It had 356 votes on Monday for the first round but needs 367 for the package to pass. If it falls between 330 and 367 in the second round, the measures will go to a referendum.
The reform package also changes the term of office to five years from seven but allows an incumbent to run again. It also calls for a four-year parliament and not five.
The opposition argues the time is not right to make such changes.
Current president Ahmet Necdet Sezer also has the power to veto the changes or call a referendum.
The BBC's Sarah Rainsford in Istanbul says the AK party believes if the people of Turkey had their say, an AK party candidate would be elected president.
The secular opposition parties have mounted a successful campaign to block Mr Gul.
They boycotted the first presidential vote in parliament and then won a constitutional court ruling that there were not enough MPs present to make Mr Gul's election valid.
The military, a strict guardian of secularism, had warned his election might endanger Turkey's system, leading the AK party to brand the constitutional court's ruling political.
The AK party denies it would push any Islamist agenda if it held both the premiership and presidency.
Our correspondent says whatever the outcome of Monday's constitutional debate, the question of who will run for president will remain.
After Sunday's failed vote, Mr Gul said his candidacy was "out of the question".
On Saturday, ahead of the vote, tens of thousands of secular Turks had protested in the towns of Manisa and Canakkale.
Earlier demonstrations in Ankara and Istanbul drew more than a million people.