Charles James Kirk, 31, a high- profile conservative activist who was an ally of Donald Trump, was shot dead during a university event in Utah on September 10. The suspected shooter, identified as Tyler Robinson, 22, has been taken into custody.

Although Kirk has never held an official position in either the government or in the Republican Party, his killing has reverberated beyond the U.S. Calling him a “giant of his generation”, Mr. Trump announced that Kirk would posthumously be awarded the Presidential Medal of Freedom — the country’s highest civilian honour. Israeli Prime Minister Benjamin Netanyahu, wanted by the International Criminal Court for war crimes, praised him as a “lion-hearted friend of Israel”, who “stood tall for Judaeo-Christian civilisation”. Luminaries of Europe’s far-right, from Alice Weidel of Germany’s neo-Nazi Alternative for Germany (AfD) to Italian Prime Minister Giorgia Meloni and Jordan Bardella of France’s National Rally have lionised Kirk, describing him as a champion of free speech and liberty.

Also read | Death of Charlie Kirk lays bare deep U.S. political divisions

It is unusual for the passing of a political organiser little known outside the U.S. to trigger such an outpouring of tributes from across the Western world. What made Kirk so special?