Islamist extremism

Could anyone explain the differences between the phrases in blue? Thanks!

In the run-up to Trump’s visit here, there was speculation about whether he would utter the phrase“radical Islamic terrorism” in his speech, the centerpiece of his Saudi trip. On the campaign trail, Trump loudly criticized Obama for refusing to describe the terrorism threat in those terms. But some of Trump’s top aides, including national security adviser H.R. McMaster, have been urging him to soften his language. Many Muslim leaders consider broad denunciations of their faith insulting.

In his Riyadh address, Trump decided to use a substitute phrase: “Islamist extremism.” But he slightly veered off the prepared excerpts released earlier by the White House, saying “Islamic” instead of “Islamist” on several occasions.