German Chancellor Angela Merkel is in Warsaw on Tuesday for talks with Poland's leaders, taking her efforts to save the European Union to a country that is keen to keep as much national power as possible and fears being marginalized in a "two-speed Europe." Ties between the two nations have been strained since the nationalistic Law and Justice party assumed power in 2015, but there are growing pressures for the neighbors and key trading partners to find common ground. Poland could benefit from better ties with Germany as US President Donald Trump seeks warmer ties with Russia, seen as a potential threat to Poland's security. Poland also will lose a key ally when Britain leaves the bloc. Merkel needs Poland's backing for reforms that will be taken up at an EU summit in March, an attempt to keep the bloc from disintegrating following Brexit. Her trip is "one of the most important visits in Polish-German relations since 2004," when Poland joined the EU, said Sebastian Plociennik, an expert at the Polish Institute of International Affairs. "The decisions made this year will set the path for the EU's future," Plociennik said. Poland's populist ruling party, Law and Justice, is often described as euroskeptic, but unlike right-wing populists in France and elsewhere, it does not advocate leaving the EU. EU membership remains hugely popular in Poland, whose citizens have benefited from development funds and the freedom to work elsewhere in the bloc. However, Law and Justice fears that Poland's national identity has been eroded by liberal Western values and it wants to preserve as much power as possible for Europe's national parliaments. Many criticize what they see as the EU's distant and inefficient bureaucracy. Poland also is not eager to join the 19-nation eurozone anytime soon. Law and Justice Chairman Jaroslaw Kaczynski maintains that the EU has become a vehicle for Germany to dominate smaller states. "I am not saying that we have no advantages," he said in an interview with the German daily Frankfurter Allgemeine Zeitung. "But Germany has more. Ms. Merkel is absolutely the No. 1 in the EU, and that is not a healthy situation." "European legislation must be reduced to its core: the common market, to some extent environmental protection," he told FAZ. "But no one can tell us how to regulate marriage or how we stand on sexual orientation." Kaczynski nonetheless endorses Merkel in Germany's September elections, dismissing her main opponent, Martin Schulz, as "a left-wing ideologue" with an "inclination toward Russia." Polish officials also worry that Merkel's advocacy of a "multi-speed" Europe could mean developing a more deeply integrated core including Germany, France and the Benelux nations, which could then dictate financial rules to other EU countries. But Poland has contributed to its marginalization within the EU by refusing to accept any refugees or give up its heavy reliance on coal. It is also in a standoff with Brussels for eroding the independence of Poland's constitutional court. Merkel is to meet with Kaczynski, Prime Minister Beata Szydlo, President Andrzej Duda, the leaders of two opposition parties and representatives of the ethnic German minority in Poland. The leaders also are at odds about re-electing of former Polish Prime Minister Donald Tusk as head of the European Council. Merkel supports Tusk but Kaczynski has indicated he won't support Tusk for another term.