What is the main issue with Europe's defense strategy?

Europe has been significantly underinvesting in its own defense for decades, instead relying heavily on the United States for protection while allocating its resources to social welfare programs. This imbalance has been consistently criticized by successive defense secretaries and presidents who have emphasized that this approach is unsustainable. The expert notes that Europe is simply not spending enough on its defense capabilities, creating a prolonged dependence on American military support that has become a point of contention in transatlantic relations.