Turkey and Europe are locked in a bitter dispute after Germany and the Netherlands blocked Turkish ministers from campaigning in the local Turkish communities for a 'yes' vote on boosting Erdogan's powers in next month's referendum.
"What? If a 'yes' comes out on April 16, they would not take us into the European Union? Oh, If only they could give this decision! They would make our work easier," Erdogan said at a rally in the southern city of Antalya.
But Erdogan told the rally that "April 16 would be a breaking point," referring to EU-Turkey relations if the 'yes' vote wins.
"We will put this (EU-Turkey) business on the table because Turkey is no one's whipping boy," he added, indicating that Ankara could reconsider its relationship with Brussels.
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And among some European politicians, there has been discussion over what the future of Turkey's membership process would be.
Kati Piri, the European Parliament's Rapporteur for Turkey, wrote for Politico Europe earlier this week that if a majority of voters approved the constitutional changes, "the European Parliament will have to assess whether the country's new governance structure meets the EU's Copenhagen accession criteria".
While the government argues it is necessary for political stability and would avoid fragile coalition governments, critics fear it will lead to one-man rule.
Erdogan has repeatedly accused European countries including Germany of using "Nazi measures" - comments that have been condemned by the bloc's leaders.
"For as long as you continue to call me dictator, I will continue to call you fascist, Nazi," Erdogan retorted.
Another contentious issue is the death penalty, which the Turkish president said again today he would approve if it was passed by parliament and brought to him.
Turkey abolished the death penalty in 2004 as part of its bid to join the EU.
But Brussels has repeatedly made clear that any move to bring it back would scupper Turkey's efforts to join the bloc.