By Justyna Pawlak and Anna Wlodarczak-Semczuk
WARSAW (Reuters) - Poland's new prime minister faces a difficult balancing act trying to repair bruised relations with the European Union without alienating the eurosceptic government's core voters.
A Western-educated former banker who is fluent in German and English and was sworn in on Monday, Mateusz Morawiecki boasts the credentials needed to negotiate with Brussels.
But any compromises to improve relations with Brussels, which sees the ruling Law and Justice (PiS) party as a threat to democracy, would risk upsetting the traditional, Catholic supporters who propelled it into power two years ago.
It is a gamble that could backfire, and it is not yet clear how far Morawiecki, 49, and his party, dominated by former Prime Minister Jaroslaw Kaczynski, are ready to go to please Brussels.
"The idea to build up international credibility seems rational," said Jaroslaw Flis, a sociologist at the Jagiellonian University. "But such actions would have to be in complete contrast with what Mateusz Morawiecki would have to do domestically to prevent the PiS from falling apart."
The PiS government has alienated many people at home and abroad with its nationalist rhetoric and changes to state institutions which the EU says subvert the bloc's laws.
The European Commission, the EU executive, opened an inquiry into the rule of law in Poland in January 2016 and the European Parliament has started a process that could deprive Poland of its voting rights in the 28-nation bloc.
Any hope in Brussels that Morawiecki's appointment signals a change of course by PiS will have been tempered by Polish parliament approving legal changes to the judiciary in defiance of the EU on Friday - the day after his nomination.
The changes give parliament, where PiS has a majority, de facto control over the selection of judges.
LOOKING FOR CLUES
EU leaders looking for clues about Morawiecki's plans will also have taken little comfort from comments he has made since being nominated, making clear he backs a tough line on the EU and believes in PiS's traditional vision of the Polish state.
"We want to transform Europe, this is my dream, to re-christianise it," Morawiecki told the Catholic Radio Maryja broadcaster. "We want Poland to be strong, but also to contain ... Christian values. We will defend them against the background of laicisation and a deepening consumerism."
Asked by the radio interviewer about demands by French President Emmanuel Macron for Poland to face sanctions over a subversion of democratic rules, Morawiecki said he would not "bow down to blackmail."
In comments to parliament on Tuesday, Morawiecki suggested Poland might relent in a conflict with Brussels over logging in an ancient forest, which an EU court has said contravenes EU laws.
But he said Poland's national interests came first in any debate over the future of the EU and that he "wholeheartedly" supported PiS's overhaul of the judiciary.
Like Beata Szydlo, whom he replaced as prime minister, Morawiecki is likely to have to defer to PiS leader and co-founder Jaroslaw Kaczynski. Prime minister from July 2006 to November 2007, Kaczynski is widely seen as the power behind the party and Poland's main decision-maker.
How much scope that will leave Morawiecki to carve out his own path remains to be seen. Former Polish President Lech Walesa, a PiS critic, has suggested that nothing of substance will change.
"The circus has stayed the same, only the clowns have changed their roles," Walesa, who led the Solidarity trade union movement that ended communist rule, said on Twitter.
The appointment of Morawiecki, whose father founded and led a radical offshoot of Solidarity in the 1980s, appears designed in part to present a new face of Poland to the EU.
Szydlo, 54, at times responded angrily to EU criticism and relations with the bloc soured under her government. Underlining PiS opposition to Muslim immigration, she said last month Poland wanted to be sure Christian traditions were not subject to "ideological censorship" in the EU.
Along with Hungary, Poland has refused to take in any of its quota of the wave of refugees from Syria and elsewhere who have come to Europe since 2015, on the grounds that Muslim immigrants are a threat to national security and stability.
Such comments appeal to core PiS voters, and Szydlo's government, which promised generous welfare payouts and a dedication to traditional Catholic values, was one of Poland's most popular since communist rule ended in 1989.
A relative newcomer to politics, Morawiecki lacks Szydlo's broad appeal. But he has overseen significant economic achievements since becoming finance minister in 2016, a position he has retained in the new government.
Tusk has welcomed what he sees as signs that Morawiecki is a liberal economist who wants better ties with the EU.
"There is no doubt that (Morawiecki's) liberal bias and some pro-western gestures could be a sign that there is a lurking desire to improve relations," Tusk said last week.
But an economic stimulus plan Morawiecki unveiled in 2016 has been criticized by economists who say it depends heavily on private investment, which is low in Poland despite fast economic growth.
"What Morawiecki sees as a solution, meaning more political influence in the economy, is actually dangerous," said Leszek Balcerowicz, a former finance minister who coordinated the transition to a market economy after decades of communist rule.
Any hint of protectionism is also likely to worry EU leaders, who seek to break down trade barriers.
Morawiecki has called the privatization of state-owned companies a tragedy and said he will give more power to domestic capital at the expense of foreign investors. In his comments to parliament on Tuesday, he said economic policy should not change.
(Reporting by Justyna Pawlak, Anna Wlodarczak-Semczuk, Anna Koper, Pawel Florkiewicz and Pawel Sobczak, Editing by Timothy Heritage)