U.K. Prime Minister Keir Starmer swept to power promising to raise living standards and grow the British economy. But now his premiership has an urgent and altogether different focus: preserving European security in a volatile world order upended by U.S. President Donald Trump.

Starmer¡¯s commitment to increase defense spending to 2.5% of the gross domestic product by 2027 and rising to 3% over the next decade ¡ª funded by cutting the aid budget ¡ª is the latest fallout from the shockwave of Trump¡¯s apparent refusal for the U.S. to be the final guarantor of security in Europe.

¡°I believe we must now change our approach to national security so we are ready to meet the challenges of our volatile world,¡± Starmer said at a press conference from Downing Street on Tuesday, as he confirmed that his decision to increase military spending had been ¡°accelerated¡± by U.S. comments and actions in recent weeks. ¡°Tyrants like Putin only respond to strength.¡±