Canada is a parliamentary constitutional monarchy with King Charles III as head of state and a federal system spanning ten provinces and three territories. Its defining external relationship is with the neighboring United States, with which it shares the world's longest land border and deep economic, security, and cultural ties, balanced against efforts to assert sovereignty over its Arctic territory amid growing interest from other powers. As a G7 member and a leading voice in multilateral institutions, it maintains close alignment with Western allies; domestically, the bilingual English-French character, federal-provincial tensions, and Indigenous reconciliation are durable fault lines. The Liberal Party, led by Prime Minister Mark Carney, currently heads the government.