A top Polish court ruled Wednesday that the European Union's Lisbon Treaty was in line with the country's constitution, DPA reported.
Right-wing parliamentarians had claimed the treaty would weaken Poland's legislature.
The Constitutional Court determined that the treaty, and the EU, recognized the national sovereignty of the organization's members. The court said that EU membership was a confirmation of Poland's sovereignty, not a limitation on or loss of sovereignty.
Some 61 members of the opposition Law and Justice party had signed a statement in November 2009 saying the treaty was incompatible with the Polish constitution and asked the court to review it.
They said the treaty would force Poland to accept EU decisions even if Polish authorities did not agree with them.
"We cannot allow for a situation in which European Union law doesn't have to reckon with the Polish constitution," parliamentarian Piotr Andrzejewski has said.
The lawmakers claimed the Lisbon Treaty would limit Polish sovereignty and allow important decisions affecting the country to be made in Brussels without agreement from the Polish parliament.
As the court gave the ruling, one man yelled, "Shame! You're rubber-stamping the partition of Poland." He was escorted out by security.
Poland's then-President Lech Kaczynski ratified the Lisbon Treaty in October 2009.