The 25th anniversary of the 9/11 attacks is being marked. Since then, US presidents have gradually expanded their powers to wage war. This trend has continued with the current president, Donald Trump, who has taken military action against Iran.

Trump's actions against Iran were taken without congressional authorization or support from NATO allies or a UN resolution. The decision was also made without public backing in the US.

Further analysis of Trump's actions and their implications is available from Peter Bergen, a CNN analyst, who has examined the expansion of presidential war powers over the past two decades.