TORONTO — As we chatted in separate interviews about their new film “Sicario,” both Emily Blunt and Josh Brolin echoed a similar theme. “If there wasn’t this incredible, insatiable demand for drugs in America — and frankly, around the world — I believe the drug cartels would be out of business pretty quickly,” said Blunt, in the Canadian city for the recently completed Toronto International Film Festival. “I also like the fact that this film explores how not everything is black and white in that world. There’s a lot of shades of gray. There’s not such a clear line between right and wrong, especially when it comes to the people who have to fight the drug lords’ brutal methods — sometimes having to resort to tough tactics themselves.”

Her co-star Brolin made the same point. “Of course it’s not an issue that’s instantly resolvable, and it’s something we’ve struggled with for decades and decades and decades. It’s a tough issue to deal with. … [President] Nixon had it. It’s about rehabilitation. If you knock the demand for drugs out, if you knock the product down, you knock the profit down, and without profits there’s no need for a cartel.”

In the film (opening Friday), Blunt portrays a FBI agent who runs a kidnap response team and is suddenly thrust into a dangerous mission to undermine and disable one of the major Mexican drug cartels. Brolin is a mysterious government operative (think CIA) working with her on the project — along with another mysterious character, portrayed by Benicio del Toro.

Blunt said the violence showcased in the film, directed by Denis Villeneuve (“Prisoners,” “Enemy”), is justified. “It’s not gratuitous, in the least. It’s in the film because that’s what the people in Mexico are facing every day for real. … It’s horrendous, and it’s absolutely real.”

On top of that, Blunt loved getting the chance to portray a woman in a field that is strongly dominated by men. “Cinematically, we don’t see that very often. There are lots of women in law enforcement, we just don’t make movies about them. … But yes, [my character] definitely is in a very testosterone-fueled world, and yet sort of holds her own.

“That said, I didn’t want to play her in a very butch, action heroine way. I think she is highly skilled at what she does, but then she’s thrust into this incoherent world where the cartel and the CIA are operating in a lawless way, every day of the week. She finds her skills are rendered completely useless, so I tried to portray her as a woman caught between vulnerability and strength.”