1462: Islamic State vs Islamic Republic Dec 12, 2018
Even though the two may be used somewhat interchangeably in lay conversations, there is an understood difference between an 'Islamic state' and an 'Islamic republic'. The former refers to a country that has Sharia as its constitution in some respect, and includes country like Saudi Arabia. In this way, on a state-level the country is Islamic, and usually this will exclude democratic elections. Meanwhile, an Islamic republic may also involve Islam on a legislative level, but it will also include more elections. Ultimately however, there is a great deal of overlaps, and these are just norms for usage.
https://www.youtube.com/playlist?list=PLzKhTxYYlal1d1-XhqPh122t6bgaNpI7A