<Dd> Poland does not deal with the issue of dual citizenship, but possession of another citizenship is tolerated since there are no penalties for its possession alone . However, penalties do exist for exercising foreign citizenship, such as identifying oneself to Polish authorities using a foreign identification document . Dual citizens are usually not exempted from their duties as Polish citizens such as entering / leaving Poland using Polish passport or Polish ID card . Under some circumstances, ethnic Poles can apply for the "Polish Card" (Karta Polaka). (see below) See also: Polish nationality law </Dd> <Dd> Portugal allows dual citizenship . See also: Portuguese nationality law </Dd> <Dd> Romania allows dual citizenship . See also: Romanian nationality law </Dd> <Dd> In Slovakia, dual citizenship is permitted to Slovak citizens who acquire a second citizenship by birth or through marriage; and to foreign nationals who apply for Slovak citizenship and meet the requirements of the Citizenship Act . Please note that after the' Hungarian - Slovak citizenship conflict' (year 2010) some restrictions to dual citizenship may apply . See also: Slovak nationality law </Dd>

How many citizenships can a us citizen have