Nawrocki announced his intention to block the bill in a televised address on Thursday.
Prime Minister Donald Tusk accused the president of squandering his chance "to act like a patriot" and convened an emergency cabinet session to approve an alternative approach.
The formal justification, published on the presidential website late Friday evening, argues that the law would have unlawfully transferred sovereignty over Poland's armed forces to EU institutions, in breach of the constitution.
At the heart of the president's case is the claim that the European Commission would have gained effective co-decision power over what weapons and equipment the Polish military purchases – a competency he argues cannot legally be delegated to any international body under Article 90 of Poland's constitution.
The document also raises concerns about the Commission's ability to withhold loan instalments and impose so-called "milestones" on Warsaw without any right of legal appeal, a mechanism Nawrocki compares to Poland's experience with the post-Covid EU recovery fund.
The veto comes after weeks of political dispute over SAFE, with the government and opposition sharply divided.
The ruling coalition has championed the programme as a rare opportunity to modernise the military and expand Poland's defence industry simultaneously – a view shared by the country's top brass, including Chief of the General Staff General Wiesław Kukuła and the head of the Armaments Agency, General Artur Kuptel.
Poland had secured the largest allocation under the SAFE programme, worth around EUR 43.7 billion, with the government pledging to direct 89 percent of the funds to domestic defence firms.
The government says it will access those funds regardless, channelling them through the Armed Forces Support Fund – an existing vehicle within state lender Bank Gospodarstwa Krajowego (BGK).
(ał)
Source: PAP