On Thursday, US President Donald Trump will announce new federal guidance to safeguard students' ability to pray in school.

Mr Trump previewed the idea during an address to evangelicals in Florida this month, praising state efforts to expand school prayer and warning against what he described as "hard left" opposition.

"I will be taking action to safeguard students' and teachers' First Amendment rights to pray in their schools," he said at the Evangelicals for Trump event in Miami. "They want to take that right along with many other rights."  

It was, in fact, the Supreme Court that cracked down on prayer in schools in the 1960s. School-sponsored prayer in public schools was ruled unconstitutional and public schools cannot sponsor prayer at graduation ceremonies. The topic continues to be one of the country's most controversial issues. 

In the 2016 presidential election, Mr Trump won 80 per cent of the votes from whites who declared themselves born-again or evangelical Christians, according to exit polling. Trump told the crowd in Miami that he expects his re-election to generate even more enthusiasm among the Christian faithful than in 2016.