Nightly exchanges of fire between the US and Iran have been the most intense since a memorandum of understanding was signed a month ago. A former US ambassador told Al Jazeera's 'T

Nightly exchanges of fire between the US and Iran have been the most intense since a memorandum of understanding was signed a month ago. A former US ambassador told Al Jazeera's 'This Is America' that Tehran had miscalculated in believing US President Trump would back down.