By Marcin Goclowski and Agnieszka Barteczko
WARSAW (Reuters) - Polish President Andrzej Duda ratified one of three judicial reform bills on Tuesday, but his veto of two others dealt a blow to the conservative Law and Justice (PiS) party and threatened to sow divisions in the coalition it heads.
Amid signals from one of PiS's junior partners that it backed the president's stance, a senior party figure denied that the coalition was in jeopardy or that an early election might be necessary.
The law ratified by Duda allows the justice minister to hire and fire the senior judges who head ordinary courts, a measure that the PiS says is needed to speed up a system widely seen as too slow and redolent of the communist era, and to make the judiciary more accountable to the people.
But he blocked other laws that would have given the government and parliament power to replace Supreme Court judges - plans that have triggered mass protests across the country and prompted concern in Brussels and Washington.
A European Union official said Poland - the bloc's biggest and most powerful East European member - could face legal consequences, in the form of a rare censure process, if it started dismissing judges.
"If mass firing of judges starts, then a red line is crossed where all dialogue will need to be declared as failed," the official said.
Critics at home and abroad accuse the conservative, nationalist-minded PiS of trying to politicize the judiciary, pointing to previous moves to increase government control over state media, state prosecutors and the Constitutional Tribunal.
The issue has divided the country, plunging into one of its deepest crises since the overthrow of Communism in 1989.
PiS appeared to be rattled by the unexpected veto announcement from Duda, who had previously appeared closely aligned with the party.
Jadwiga Emilewicz, deputy development minister and a member of the small right-wing Polska Razem party, tweeted her approval of his intervention: "Legislative initiative in president's court. This is a good solution for Poland".
PiS needs Polska Razem's nine seats to maintain its lower house majority. Asked about the possibility of a coalition break-up, PiS's deputy parliamentary speaker, Ryszard Terlecki said: "I don't see a risk of that, at least for now... There is no war at the top."
Terlecki told reporters there was no reason to hold an early election, and the government could keep going another two years, to the end of its term.
Polska Razem said in a statement that, while it broadly agreed with Duda's view of the bills he vetoed, it had not considered voting against the government because "it is obvious that a division in the coalition on such important bills would have to lead to an early election".
The three main opposition parties, Civic Platform, Nowoczesna and Polskie Stronnictwo Ludowe, held a news conference to announce a joint effort to produce their own judicial reform plan.
Ryszard Petru, the head of Nowoczesna, said he expected more street protests after Duda issued his proposals.
"Let's remember that this was one battle," he said. "It may be that we're facing further battles in the autumn."
PiS under its founder and leading light Jaroslaw Kaczynski has already ridden out a number of setbacks without a significant loss of support in its core small-town voter base, notably when street protests and an opposition blockade forced it to abandon plans to tighten the abortion law and restrict media access to parliament.
However, recent surveys have shown the combined opposition drawing level with the PiS-led coalition.
A poll published on Tuesday in the Gazeta Wyborcza daily, conducted before Duda announced his vetoes, put the PiS-led coalition on 33 percent, with the centrist Civic Platform and Nowoczesna on 23 and 9 percent respectively.
Some analysts suggest that the approach of the next parliamentary and presidential elections, respectively two and three years away, is starting to erode the stability of the government.
Witold Sokala, a political scientist at Kielce University, said Duda's decision to challenge Kaczynski had chipped away at the PiS's stranglehold over Polish politics. "The monolith of power is breaking up," he told the state news agency PAP.
Deputy Justice Minister Patryk Jaki, a PiS member, said he was disappointed with Duda's decision and gave an ambivalent reply when asked if the ministry would cooperate with president on alternative proposals that Duda is due to put forward.
"Difficult initiatives can be undertaken only when there is a conviction that it makes sense. We will not be embarking ondifficult undertakings and treating them as a goal in themselves if we know that, for example, they will be vetoed in the end."
(Additional reporting by Pawel Florkiewicz, Anna Koper, Anna Wlodarczak-Semczuk.; Writing by Kevin Liffey and Mark Trevelyan)