An Israeli Arab party that broke with its allies and refused to back Benny Gantz, the former army chief, as Israel’s next leader said Thursday that his policies were “virtually indistinguishable” from those of Prime Minister Benjamin Netanyahu, who is widely reviled by the country’s Arab minority.

The party, Balad, was responding to what its leader described as a torrent of criticism that, by withholding an endorsement of Mr. Gantz, Balad had improved Mr. Netanyahu’s prospects for keeping his post as prime minister.

The Balad leader, Mtanes Shehadeh, said in an opinion article published by Israel’s Haaretz newspaper that most of that criticism is “unjustified and politically baseless.” He said that an endorsement of Mr. Gantz would have “obliged us to stray from the ideological principles that have guided us.”

The uncertain outcome of the Israeli election last week meant that President Reuven Rivlin had to decide which of the two leading contenders should have the first right to assemble a coalition government. On Wednesday, Mr. Rivlin chose Mr. Netanyahu, who has 28 days to assemble a parliamentary majority of at least 61 seats.