Turkish President Recep Tayyip Erdogan has approved a constitutional reform bill, paving the way for a referendum on switching to an executive presidential system with sweeping powers.

PM Binali Yildirim said on February 10 that the referendum could be held on April 16.

Main opposition party CHP says the presidential system will undermine the country’s democratic institutions and will lead to one-man rule in a country with few checks and balances. But the government rejects such claims, arguing that presidential rule will only deliver more political stability and a stronger economy through more effective governance.

The parliamentary debate on the controversial changes several times led to violent clashes between MPs. Eventually, the 18-article bill received 339 votes in the 550-seat parliament.

The ruling AKP and the opposition Nationalist Movement Party (MHP) voted in favour of the fundamental constitutional changes.

The governing party garnered 49.5% of the vote in the November 2015 general election, while the MHP took 10.8%.

Some analysts, however, still think the referendum will be a close call. They point to disgruntled MHP supporters not convinced that Erdogan should have so much power in his hands.

Several polls have suggested the MHP’s grassroots will vote against the constitutional reforms in the referendum. Public opinion surveys in Turkey are typically seen as misleading.