Turkey’s parliament has introduced new election rules the government says will better secure ballots, while the opposition says the overhaul could lead to fraud and undermine the integrity of a slate of polls scheduled for next year.

So charged is the debate over the changes that a fistfight erupted between lawmakers during the 20-hour marathon session that wrapped Tuesday morning. President Recep Tayyip Erdogan, whose party drafted the bill with parliament’s smallest party, is now expected to sign it into law.

The changes allow political parties that form an alliance with a bigger party to win seats in parliament even if they fall below the national vote threshold of 10%. The new rule will allow Erdogan’s ruling Justice and Development Party (AKP) to run with the far-right Nationalist Action Party, which it has worked closely with since a failed 2016 coup attempt and subsequent state of emergency.

The legislation also allows ballots that are not stamped by election officials or stamped multiple times to be admitted, formalizing a controversial measure in a 2017 constitutional referendum in which unvalidated ballots were counted.