The bill to launch a special counsel investigation into allegations surrounding First Lady Kim Keon-hee was struck down in a National Assembly vote late Thursday, amid a loud protest from the Democratic Party of Korea’s primary losers challenging the results of the nominations for the April general election.

The ruling People Power Party and the main opposition Democratic Party convened a plenary session to vote on the special counsel bill, which was sent back to the Assembly for a re-vote following a presidential veto.

The bill was blocked with 171 voting in favor and 109 against. One vote was deemed invalid. To pass, the bill needed at least 188 votes in favor. When the special counsel investigation bill against the first lady was put to vote in December, it passed in the absence of ruling party lawmakers, who protested with a collective boycott.

As the Democratic Party controls the majority of the Assembly’s majority, holding 54 percent of total seats, passing the opposition-backed bill for a second time should not have a problem, observers say.

The failure to pass the bill may have to do with a deepening divide within the Democratic Party, between lawmakers aligned with its leader Rep. Lee Jae-myung and those who are not.

Namely lawmakers who are identified as pro-Moon Jae-in, the last Democratic Party president, suffered a harsh blow, losing nominations to Lee-aligned rivals.

Rep. Sul Hoon, yet another pro-Moon lawmaker who is deserting the Democratic Party in protest of the bias in the primary results, said Thursday that the party was “eliminating Moon allies.”

Even among the Democratic Party leadership, disagreements on the way the party was deciding who gets to run for the upcoming general election.

Rep. Ko Min-jung said she would step down from the supreme council, the party’s top decision-making body, and Rep. Hong Ihk-pyo, the Democratic Party floor leader, said he didn’t agree with some of the pro-Moon lawmakers being ruled out.

Speaking to reporters after Thursday’s plenary session, the ruling party floor leader Rep. Yun Jae-ok was reluctant to associate the results of the vote with the opposition’s internal clash.

“I think it’s better to end the debate on this bill, since it was voted down anyway. I see no need for extra interpretations on what happened,” he said.