"The fact that there are so many weapons still in that country shows that the second amendment right to bear arms, has been weaponised to sell guns to hurt more people, and Americans are held hostage by NRA lobbyists."

Campbell won last year's Judith Johnson award for best performance by a male actor in a leading role in a musical at the Sydney Theatre Awards. Now after a sold-out season at the Hayes, the Stephen Sondheim musical is set for a return performance, opening at the Opera House on Tuesday.

Since the show opened at the Hayes, calls for gun control have been consistently in the headlines, most notably in March when the students of Parkland led a mass rally in Washington called March For Our Lives.

"When we did the show last time everyone was up in arms about Trump but now, since the school shooting in Parkland, Florida, Assassins has become way more resonant and frightening in different ways," musical director Andrew Worboys says.

"A musical about killing presidents set in a carnival breaks all the rules of a standard traditional musical comedy. It's Sondheim's favourite piece. In his mind it's his most accessible musical, and obviously – sadly – it is always going to be topical.

Since 1990, when Sondheim wrote the music and lyrics, there have been more than 300 school shootings.

Lisa Campbell, the show's producer, sees parallels between the motivations of Booth, who was a passionate champion of the American south during the Civil War, and the current state of world politics."In the play there is this mournful longing for another time which articulates a lot of what people voting for Donald Trump were on about," she says. "We see it in Trump, we see it in Brexit, we see it in Pauline Hanson, this feeling that the times before were halcyon days – this political rhetoric has been going on since the Civil War."

Assassins The Musical, the third Hayes production to go to the Opera House since it began in Darlinghurst in 2014, will run at the Opera House until July 1.